Cleanup namespace usage in platform/graphics/[filters/* to skia/*] and platform/graphics/[B-D]*

Source/platform/graphics/gpu/WebGLImageBufferSurface.h

Index: Source/platform/graphics/gpu/WebGLImageBufferSurface.h
diff --git a/Source/platform/graphics/gpu/WebGLImageBufferSurface.h b/Source/platform/graphics/gpu/WebGLImageBufferSurface.h
index 3d705b536c8a3545abd80dd8963f7bdad51c0828..281600dc707f21688f1f06fab7980eebd9d5983b 100644
--- a/Source/platform/graphics/gpu/WebGLImageBufferSurface.h
+++ b/Source/platform/graphics/gpu/WebGLImageBufferSurface.h
@@ -36,10 +36,8 @@
 #include "wtf/OwnPtr.h"
 
 namespace blink {
-class WebGraphicsContext3DProvider;
-}
 
-namespace blink {
+class WebGraphicsContext3DProvider;
 
 // This is a GPU backed surface that has no canvas or render target.
 class PLATFORM_EXPORT WebGLImageBufferSurface : public ImageBufferSurface {
@@ -63,10 +61,9 @@ private:
     // This raw-pixel based SkBitmap works as a cache at CPU side to avoid heavy cost
     // on readback from GPU side to CPU side in some cases.
     SkBitmap m_cachedBitmap;
-    OwnPtr<blink::WebGraphicsContext3DProvider> m_contextProvider;
+    OwnPtr<WebGraphicsContext3DProvider> m_contextProvider;
 };
 
-
 } // namespace blink
 
 #endif