Introduce content::RenderWidgetHostViewPort (in content/port/browser).

chrome/browser/tab_contents/thumbnail_generator_unittest.cc

Index: chrome/browser/tab_contents/thumbnail_generator_unittest.cc
diff --git a/chrome/browser/tab_contents/thumbnail_generator_unittest.cc b/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
index 885577a2e8b7a99e54521a5d73c4903c90c9eccb..ccba5651c91fd46f99dfde7a65e6fe6775ea90bc 100644
--- a/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
+++ b/chrome/browser/tab_contents/thumbnail_generator_unittest.cc
@@ -40,10 +40,10 @@ static const int kBitmapHeight = 100;
 // works. The skia implementation doesn't have any hardware or system
 // dependencies.
 class TestRenderWidgetHostViewWithBackingStoreSkia
-    : public TestRenderWidgetHostView {
+    : public content::TestRenderWidgetHostView {
  public:
   explicit TestRenderWidgetHostViewWithBackingStoreSkia(RenderWidgetHost* rwh)
-      : TestRenderWidgetHostView(rwh), rwh_(rwh) {}
+      : content::TestRenderWidgetHostView(rwh), rwh_(rwh) {}
 
   BackingStore* AllocBackingStore(const gfx::Size& size) {
     return new BackingStoreSkia(rwh_, size);