Inflate dirty rect by 1 pixel on a high DPI display

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index bbb84dfe6c146ba654773992d7091c485dea1de6..80b155df9a4992044da83d99365fcd24c4f693b2 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -269,6 +269,8 @@ void HTMLCanvasElement::didDraw(const FloatRect& rect)
     clearCopiedImage();
     if (layoutObject())
         layoutObject()->setMayNeedPaintInvalidation();
+    if (m_context && m_context->is2d() && m_context->shouldAntialias())
+        m_dirtyRect.inflate(1);
     m_dirtyRect.unite(rect);
     if (m_context && m_context->is2d() && hasImageBuffer())
         buffer()->didDraw(rect);