diff -r 000000000000 -r 6474c204b198 layout/generic/nsLeafFrame.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/generic/nsLeafFrame.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,107 @@
+/* -*- Mode: C++; tab-width: 2; 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/. */
+
+/* base class for rendering objects that do not have child lists */
+
+#ifndef nsLeafFrame_h___
+#define nsLeafFrame_h___
+
+#include "mozilla/Attributes.h"
+#include "nsFrame.h"
+#include "nsDisplayList.h"
+
+/**
+ * Abstract class that provides simple fixed-size layout for leaf objects
+ * (e.g. images, form elements, etc.). Deriviations provide the implementation
+ * of the GetDesiredSize method. The rendering method knows how to render
+ * borders and backgrounds.
+ */
+class nsLeafFrame : public nsFrame {
+public:
+  NS_DECL_FRAMEARENA_HELPERS
+
+  // nsIFrame replacements
+  virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
+                                const nsRect&           aDirtyRect,
+                                const nsDisplayListSet& aLists) MOZ_OVERRIDE {
+    DO_GLOBAL_REFLOW_COUNT_DSP("nsLeafFrame");
+    DisplayBorderBackgroundOutline(aBuilder, aLists);
+  }
+
+  /**
+   * Both GetMinWidth and GetPrefWidth will return whatever GetIntrinsicWidth
+   * returns.
+   */
+  virtual nscoord GetMinWidth(nsRenderingContext *aRenderingContext) MOZ_OVERRIDE;
+  virtual nscoord GetPrefWidth(nsRenderingContext *aRenderingContext) MOZ_OVERRIDE;
+
+  /**
+   * Our auto size is just intrinsic width and intrinsic height.
+   */
+  virtual nsSize ComputeAutoSize(nsRenderingContext *aRenderingContext,
+                                 nsSize aCBSize, nscoord aAvailableWidth,
+                                 nsSize aMargin, nsSize aBorder,
+                                 nsSize aPadding, bool aShrinkWrap) MOZ_OVERRIDE;
+
+  /**
+   * Reflow our frame.  This will use the computed width plus borderpadding for
+   * the desired width, and use the return value of GetIntrinsicHeight plus
+   * borderpadding for the desired height.  Ascent will be set to the height,
+   * and descent will be set to 0.
+   */
+  virtual nsresult Reflow(nsPresContext*      aPresContext,
+                          nsHTMLReflowMetrics& aDesiredSize,
+                          const nsHTMLReflowState& aReflowState,
+                          nsReflowStatus&      aStatus) MOZ_OVERRIDE;
+  
+  /**
+   * This method does most of the work that Reflow() above need done.
+   */
+  virtual nsresult DoReflow(nsPresContext*      aPresContext,
+                            nsHTMLReflowMetrics& aDesiredSize,
+                            const nsHTMLReflowState& aReflowState,
+                            nsReflowStatus&      aStatus);
+
+  virtual bool IsFrameOfType(uint32_t aFlags) const MOZ_OVERRIDE
+  {
+    // We don't actually contain a block, but we do always want a
+    // computed width, so tell a little white lie here.
+    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplacedContainsBlock));
+  }
+
+protected:
+  nsLeafFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
+  virtual ~nsLeafFrame();
+
+  /**
+   * Return the intrinsic width of the frame's content area. Note that this
+   * should not include borders or padding and should not depend on the applied
+   * styles.
+   */
+  virtual nscoord GetIntrinsicWidth() = 0;
+
+  /**
+   * Return the intrinsic height of the frame's content area.  This should not
+   * include border or padding.  This will only matter if the specified height
+   * is auto.  Note that subclasses must either implement this or override
+   * Reflow and ComputeAutoSize; the default Reflow and ComputeAutoSize impls
+   * call this method.
+   */
+  virtual nscoord GetIntrinsicHeight();
+
+  /**
+   * Subroutine to add in borders and padding
+   */
+  void AddBordersAndPadding(const nsHTMLReflowState& aReflowState,
+                            nsHTMLReflowMetrics& aDesiredSize);
+
+  /**
+   * Set aDesiredSize to be the available size
+   */
+  void SizeToAvailSize(const nsHTMLReflowState& aReflowState,
+                       nsHTMLReflowMetrics& aDesiredSize);
+};
+
+#endif /* nsLeafFrame_h___ */