color: Set GpuMemoryBuffer color spaces for Canvas

gpu/ipc/common/surface_handle.h

Index: gpu/ipc/common/surface_handle.h
diff --git a/gpu/ipc/common/surface_handle.h b/gpu/ipc/common/surface_handle.h
index a0009b2ab03431aab12ba255835293d8b5778fb6..70659ab5b521dafe909bc41884abd52746647459 100644
--- a/gpu/ipc/common/surface_handle.h
+++ b/gpu/ipc/common/surface_handle.h
@@ -29,10 +29,10 @@ namespace gpu {
 // be defined, because some APIs that use it are referenced there.
 #if defined(GPU_SURFACE_HANDLE_IS_ACCELERATED_WINDOW)
 using SurfaceHandle = gfx::AcceleratedWidget;
-const SurfaceHandle kNullSurfaceHandle = gfx::kNullAcceleratedWidget;
+constexpr SurfaceHandle kNullSurfaceHandle = gfx::kNullAcceleratedWidget;

[ccameron, 2016/09/29 20:47:53]

This is not strictly necessary, but it'll be needed if anyone wants to use
gpu::kNullSurfaceHandle in the way that we use gfx::NullAcceleratedWidget here.

 #elif defined(OS_MACOSX) || defined(OS_ANDROID) || defined(OS_NACL)
 using SurfaceHandle = int32_t;
-const SurfaceHandle kNullSurfaceHandle = 0;
+constexpr SurfaceHandle kNullSurfaceHandle = 0;
 #else
 #error Platform not supported.
 #endif