Add a command-line flag to set GPU rasterization multisampling.

content/renderer/gpu/compositor_dependencies.h

Index: content/renderer/gpu/compositor_dependencies.h
diff --git a/content/renderer/gpu/compositor_dependencies.h b/content/renderer/gpu/compositor_dependencies.h
index 90251bb64794939c320d2afe7664a847f7ae437f..fb1396272752d63d3307e244f1e9b7b9078ee138 100644
--- a/content/renderer/gpu/compositor_dependencies.h
+++ b/content/renderer/gpu/compositor_dependencies.h
@@ -30,6 +30,7 @@ class CompositorDependencies {
   virtual bool IsImplSidePaintingEnabled() = 0;
   virtual bool IsGpuRasterizationForced() = 0;
   virtual bool IsGpuRasterizationEnabled() = 0;
+  virtual int GpuRasterizationMSAASampleCount() = 0;

[danakj, 2015/01/26 21:04:32]

GetGpu*

[Stephen White, 2015/01/26 22:39:51]

Done.

   virtual bool IsLcdTextEnabled() = 0;
   virtual bool IsDistanceFieldTextEnabled() = 0;
   virtual bool IsZeroCopyEnabled() = 0;