diff -r 000000000000 -r 6474c204b198 gfx/layers/Compositor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/Compositor.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,213 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/layers/Compositor.h"
+#include "base/message_loop.h"          // for MessageLoop
+#include "mozilla/layers/CompositorParent.h"  // for CompositorParent
+#include "mozilla/layers/Effects.h"     // for Effect, EffectChain, etc
+#include "mozilla/mozalloc.h"           // for operator delete, etc
+#include "gfx2DGlue.h"
+
+namespace mozilla {
+namespace gfx {
+class Matrix4x4;
+}
+
+namespace layers {
+
+/* static */ LayersBackend Compositor::sBackend = LayersBackend::LAYERS_NONE;
+/* static */ LayersBackend
+Compositor::GetBackend()
+{
+  AssertOnCompositorThread();
+  return sBackend;
+}
+
+/* static */ void
+Compositor::SetBackend(LayersBackend backend)
+{
+  if (sBackend != LayersBackend::LAYERS_NONE && sBackend != backend) {
+    // Assert this once we figure out bug 972891.
+    //MOZ_CRASH("Trying to use more than one OMTC compositor.");
+
+#ifdef XP_MACOSX
+    printf("ERROR: Changing compositor from %u to %u.\n",
+           unsigned(sBackend), unsigned(backend));
+#endif
+  }
+  sBackend = backend;
+}
+
+/* static */ void
+Compositor::AssertOnCompositorThread()
+{
+  MOZ_ASSERT(CompositorParent::CompositorLoop() ==
+             MessageLoop::current(),
+             "Can only call this from the compositor thread!");
+}
+
+bool
+Compositor::ShouldDrawDiagnostics(DiagnosticFlags aFlags)
+{
+  if ((aFlags & DIAGNOSTIC_TILE) && !(mDiagnosticTypes & DIAGNOSTIC_TILE_BORDERS)) {
+    return false;
+  }
+  if ((aFlags & DIAGNOSTIC_BIGIMAGE) &&
+      !(mDiagnosticTypes & DIAGNOSTIC_BIGIMAGE_BORDERS)) {
+    return false;
+  }
+  if (!mDiagnosticTypes) {
+    return false;
+  }
+  return true;
+}
+
+void
+Compositor::DrawDiagnostics(DiagnosticFlags aFlags,
+                            const nsIntRegion& aVisibleRegion,
+                            const gfx::Rect& aClipRect,
+                            const gfx::Matrix4x4& aTransform,
+                            uint32_t aFlashCounter)
+{
+  if (!ShouldDrawDiagnostics(aFlags)) {
+    return;
+  }
+
+  if (aVisibleRegion.GetNumRects() > 1) {
+    nsIntRegionRectIterator screenIter(aVisibleRegion);
+
+    while (const nsIntRect* rect = screenIter.Next())
+    {
+      DrawDiagnostics(aFlags | DIAGNOSTIC_REGION_RECT,
+                      ToRect(*rect), aClipRect, aTransform, aFlashCounter);
+    }
+  }
+
+  DrawDiagnostics(aFlags, ToRect(aVisibleRegion.GetBounds()),
+                  aClipRect, aTransform, aFlashCounter);
+}
+
+void
+Compositor::DrawDiagnostics(DiagnosticFlags aFlags,
+                            const gfx::Rect& aVisibleRect,
+                            const gfx::Rect& aClipRect,
+                            const gfx::Matrix4x4& aTransform,
+                            uint32_t aFlashCounter)
+{
+  if (!ShouldDrawDiagnostics(aFlags)) {
+    return;
+  }
+
+  DrawDiagnosticsInternal(aFlags, aVisibleRect, aClipRect, aTransform,
+                          aFlashCounter);
+}
+
+gfx::Rect
+Compositor::ClipRectInLayersCoordinates(gfx::Rect aClip) const {
+  gfx::Rect result;
+  aClip = aClip + GetCurrentRenderTarget()->GetOrigin();
+  gfx::IntSize destSize = GetWidgetSize();
+
+  switch (mScreenRotation) {
+    case ROTATION_0:
+      result = aClip;
+      break;
+    case ROTATION_90:
+      result = gfx::Rect(aClip.y,
+                         destSize.width - aClip.x - aClip.width,
+                         aClip.height, aClip.width);
+      break;
+    case ROTATION_270:
+      result = gfx::Rect(destSize.height - aClip.y - aClip.height,
+                         aClip.x,
+                         aClip.height, aClip.width);
+      break;
+    case ROTATION_180:
+      result = gfx::Rect(destSize.width - aClip.x - aClip.width,
+                         destSize.height - aClip.y - aClip.height,
+                         aClip.width, aClip.height);
+      break;
+      // ScreenRotation has a sentinel value, need to catch it in the switch
+      // statement otherwise the build fails (-WError)
+    default: {}
+  }
+  return result;
+}
+
+void
+Compositor::DrawDiagnosticsInternal(DiagnosticFlags aFlags,
+                                    const gfx::Rect& aVisibleRect,
+                                    const gfx::Rect& aClipRect,
+                                    const gfx::Matrix4x4& aTransform,
+                                    uint32_t aFlashCounter)
+{
+#ifdef MOZ_B2G
+  int lWidth = 4;
+#elif defined(ANDROID)
+  int lWidth = 10;
+#else
+  int lWidth = 2;
+#endif
+  float opacity = 0.7f;
+
+  gfx::Color color;
+  if (aFlags & DIAGNOSTIC_CONTENT) {
+    color = gfx::Color(0.0f, 1.0f, 0.0f, 1.0f); // green
+    if (aFlags & DIAGNOSTIC_COMPONENT_ALPHA) {
+      color = gfx::Color(0.0f, 1.0f, 1.0f, 1.0f); // greenish blue
+    }
+  } else if (aFlags & DIAGNOSTIC_IMAGE) {
+    color = gfx::Color(1.0f, 0.0f, 0.0f, 1.0f); // red
+  } else if (aFlags & DIAGNOSTIC_COLOR) {
+    color = gfx::Color(0.0f, 0.0f, 1.0f, 1.0f); // blue
+  } else if (aFlags & DIAGNOSTIC_CONTAINER) {
+    color = gfx::Color(0.8f, 0.0f, 0.8f, 1.0f); // purple
+  }
+
+  // make tile borders a bit more transparent to keep layer borders readable.
+  if (aFlags & DIAGNOSTIC_TILE ||
+      aFlags & DIAGNOSTIC_BIGIMAGE ||
+      aFlags & DIAGNOSTIC_REGION_RECT) {
+    lWidth = 1;
+    opacity = 0.5f;
+    color.r *= 0.7f;
+    color.g *= 0.7f;
+    color.b *= 0.7f;
+  }
+
+  if (mDiagnosticTypes & DIAGNOSTIC_FLASH_BORDERS) {
+    float flash = (float)aFlashCounter / (float)DIAGNOSTIC_FLASH_COUNTER_MAX;
+    color.r *= flash;
+    color.g *= flash;
+    color.b *= flash;
+  }
+
+  EffectChain effects;
+
+  effects.mPrimaryEffect = new EffectSolidColor(color);
+  // left
+  this->DrawQuad(gfx::Rect(aVisibleRect.x, aVisibleRect.y,
+                           lWidth, aVisibleRect.height),
+                 aClipRect, effects, opacity,
+                 aTransform);
+  // top
+  this->DrawQuad(gfx::Rect(aVisibleRect.x + lWidth, aVisibleRect.y,
+                           aVisibleRect.width - 2 * lWidth, lWidth),
+                 aClipRect, effects, opacity,
+                 aTransform);
+  // right
+  this->DrawQuad(gfx::Rect(aVisibleRect.x + aVisibleRect.width - lWidth, aVisibleRect.y,
+                           lWidth, aVisibleRect.height),
+                 aClipRect, effects, opacity,
+                 aTransform);
+  // bottom
+  this->DrawQuad(gfx::Rect(aVisibleRect.x + lWidth, aVisibleRect.y + aVisibleRect.height-lWidth,
+                           aVisibleRect.width - 2 * lWidth, lWidth),
+                 aClipRect, effects, opacity,
+                 aTransform);
+}
+
+} // namespace
+} // namespace