diff -r 000000000000 -r 6474c204b198 content/base/public/nsViewportInfo.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/public/nsViewportInfo.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,111 @@
+/* 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/. */
+
+#ifndef nsViewportInfo_h___
+#define nsViewportInfo_h___
+
+#include <stdint.h>
+#include "mozilla/Attributes.h"
+#include "Units.h"
+
+/**
+ * Default values for the nsViewportInfo class.
+ */
+static const mozilla::LayoutDeviceToScreenScale kViewportMinScale(0.0f);
+static const mozilla::LayoutDeviceToScreenScale kViewportMaxScale(10.0f);
+static const mozilla::CSSIntSize kViewportMinSize(200, 40);
+static const mozilla::CSSIntSize kViewportMaxSize(10000, 10000);
+static const int32_t  kViewportDefaultScreenWidth = 980;
+
+/**
+ * Information retrieved from the <meta name="viewport"> tag. See
+ * nsContentUtils::GetViewportInfo for more information on this functionality.
+ */
+class MOZ_STACK_CLASS nsViewportInfo
+{
+  public:
+    nsViewportInfo(const mozilla::ScreenIntSize& aDisplaySize,
+                   bool aAllowZoom = true, bool aAllowDoubleTapZoom = true) :
+      mDefaultZoom(1.0),
+      mAutoSize(true),
+      mAllowZoom(aAllowZoom),
+      mAllowDoubleTapZoom(aAllowDoubleTapZoom)
+    {
+        mSize = mozilla::gfx::RoundedToInt(mozilla::ScreenSize(aDisplaySize) / mDefaultZoom);
+        mozilla::CSSToLayoutDeviceScale pixelRatio(1.0f);
+        mMinZoom = pixelRatio * kViewportMinScale;
+        mMaxZoom = pixelRatio * kViewportMaxScale;
+        ConstrainViewportValues();
+    }
+
+    nsViewportInfo(const mozilla::CSSToScreenScale& aDefaultZoom,
+                   const mozilla::CSSToScreenScale& aMinZoom,
+                   const mozilla::CSSToScreenScale& aMaxZoom,
+                   const mozilla::CSSIntSize& aSize,
+                   bool aAutoSize,
+                   bool aAllowZoom,
+                   bool aAllowDoubleTapZoom) :
+                     mDefaultZoom(aDefaultZoom),
+                     mMinZoom(aMinZoom),
+                     mMaxZoom(aMaxZoom),
+                     mSize(aSize),
+                     mAutoSize(aAutoSize),
+                     mAllowZoom(aAllowZoom),
+                     mAllowDoubleTapZoom(aAllowDoubleTapZoom)
+    {
+      ConstrainViewportValues();
+    }
+
+    mozilla::CSSToScreenScale GetDefaultZoom() { return mDefaultZoom; }
+    void SetDefaultZoom(const mozilla::CSSToScreenScale& aDefaultZoom);
+    mozilla::CSSToScreenScale GetMinZoom() { return mMinZoom; }
+    mozilla::CSSToScreenScale GetMaxZoom() { return mMaxZoom; }
+
+    mozilla::CSSIntSize GetSize() { return mSize; }
+
+    bool IsAutoSizeEnabled() { return mAutoSize; }
+    bool IsZoomAllowed() { return mAllowZoom; }
+    bool IsDoubleTapZoomAllowed() { return mAllowDoubleTapZoom; }
+
+    void SetAllowDoubleTapZoom(bool aAllowDoubleTapZoom) { mAllowDoubleTapZoom = aAllowDoubleTapZoom; }
+
+  private:
+
+    /**
+     * Constrain the viewport calculations from the
+     * nsContentUtils::GetViewportInfo() function in order to always return
+     * sane minimum/maximum values.
+     */
+    void ConstrainViewportValues();
+
+    // Default zoom indicates the level at which the display is 'zoomed in'
+    // initially for the user, upon loading of the page.
+    mozilla::CSSToScreenScale mDefaultZoom;
+
+    // The minimum zoom level permitted by the page.
+    mozilla::CSSToScreenScale mMinZoom;
+
+    // The maximum zoom level permitted by the page.
+    mozilla::CSSToScreenScale mMaxZoom;
+
+    // The size of the viewport, specified by the <meta name="viewport"> tag.
+    mozilla::CSSIntSize mSize;
+
+    // Whether or not we should automatically size the viewport to the device's
+    // width. This is true if the document has been optimized for mobile, and
+    // the width property of a specified <meta name="viewport"> tag is either
+    // not specified, or is set to the special value 'device-width'.
+    bool mAutoSize;
+
+    // Whether or not the user can zoom in and out on the page. Default is true.
+    bool mAllowZoom;
+
+    // Whether or not the user can double-tap to zoom in. When this is disabled
+    // we can dispatch click events faster on a single tap because we don't have
+    // to wait to detect the double-tap
+    bool mAllowDoubleTapZoom;
+};
+
+#endif
+