Merge 114791 - [chromium] Clip TransparencyWin to prevent OOM from large Skia canvas

Source/WebCore/platform/graphics/chromium/TransparencyWin.cpp

Index: Source/WebCore/platform/graphics/chromium/TransparencyWin.cpp
===================================================================
--- Source/WebCore/platform/graphics/chromium/TransparencyWin.cpp	(revision 115490)
+++ Source/WebCore/platform/graphics/chromium/TransparencyWin.cpp	(working copy)
@@ -210,11 +210,19 @@
         // uses the variable: to determine how to translate things to account
         // for the offset of the layer.
         m_transformedSourceRect = m_sourceRect;
-        m_layerSize = IntSize(m_sourceRect.width(), m_sourceRect.height());
-    } else {
+    } else if (m_transformMode == KeepTransform && m_layerMode != TextComposite) {
+        // FIXME: support clipping for other modes
+        IntRect clippedSourceRect = m_sourceRect;
+        SkRect clipBounds;
+        if (m_destContext->platformContext()->canvas()->getClipBounds(&clipBounds)) {
+            FloatRect clipRect(clipBounds.left(), clipBounds.top(), clipBounds.width(), clipBounds.height());
+            clippedSourceRect.intersect(enclosingIntRect(clipRect));
+        }
+        m_transformedSourceRect = m_orgTransform.mapRect(clippedSourceRect);
+    } else
         m_transformedSourceRect = m_orgTransform.mapRect(m_sourceRect);
-        m_layerSize = IntSize(m_transformedSourceRect.width(), m_transformedSourceRect.height());
-    }
+
+    m_layerSize = IntSize(m_transformedSourceRect.width(), m_transformedSourceRect.height());
 }
 
 void TransparencyWin::setupLayer()