Adding WebThread and new BlinkPlatformImpl for utility thread.

content/utility/utility_thread_impl.h

Index: content/utility/utility_thread_impl.h
diff --git a/content/utility/utility_thread_impl.h b/content/utility/utility_thread_impl.h
index 4f0fa3f18916e7a7cc3f942661b4097e0ee24389..d6c1654df2686f4cff64aa84ef6f6446ad8fd52e 100644
--- a/content/utility/utility_thread_impl.h
+++ b/content/utility/utility_thread_impl.h
@@ -13,6 +13,7 @@
 #include "content/child/child_thread_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/utility/utility_thread.h"
+#include "content/utility/utility_blink_platform_impl.h"
 
 namespace base {
 class FilePath;
@@ -56,7 +57,7 @@ class UtilityThreadImpl : public UtilityThread,
   // True when we're running in batch mode.
   bool batch_mode_;
 
-  scoped_ptr<BlinkPlatformImpl> blink_platform_impl_;
+  scoped_ptr<UtilityBlinkPlatformImpl> blink_platform_impl_;
 
   DISALLOW_COPY_AND_ASSIGN(UtilityThreadImpl);
 };