Move a bunch of code in content\common (as well as a few left in renderer) to the content namespace.

content/common/gpu/gpu_watchdog.h

Index: content/common/gpu/gpu_watchdog.h
===================================================================
--- content/common/gpu/gpu_watchdog.h	(revision 163290)
+++ content/common/gpu/gpu_watchdog.h	(working copy)
@@ -5,6 +5,8 @@
 #ifndef CONTENT_COMMON_GPU_GPU_WATCHDOG_H_
 #define CONTENT_COMMON_GPU_GPU_WATCHDOG_H_
 
+namespace content {
+
 // Interface for objects that monitor the a GPUProcessor's progress. The
 // GPUProcessor will regularly invoke CheckArmed.
 class GpuWatchdog {
@@ -19,4 +21,6 @@
   DISALLOW_COPY_AND_ASSIGN(GpuWatchdog);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_COMMON_GPU_GPU_WATCHDOG_H_