Collect GL_EXTENSIONS string in GPUInfo and display it in about:gpu page....

chrome/common/gpu_info.h

Index: chrome/common/gpu_info.h
===================================================================
--- chrome/common/gpu_info.h	(revision 72186)
+++ chrome/common/gpu_info.h	(working copy)
@@ -79,6 +79,10 @@
   // Return "" if we are not using OpenGL.
   std::string gl_renderer() const;
 
+  // Return the GL_EXTENSIONS string.
+  // Return "" if we are not using OpenGL.
+  std::string gl_extensions() const;
+
   // Return the device semantics, i.e. whether the Vista and Windows 7 specific
   // semantics are available.
   bool can_lose_context() const;
@@ -103,6 +107,8 @@
 
   void SetGLRenderer(const std::string& gl_renderer);
 
+  void SetGLExtensions(const std::string& gl_extensions);
+
   void SetCanLoseContext(bool can_lose_context);
 
 #if defined(OS_WIN)
@@ -125,6 +131,7 @@
   std::string gl_version_string_;
   std::string gl_vendor_;
   std::string gl_renderer_;
+  std::string gl_extensions_;
   bool can_lose_context_;
 
 #if defined(OS_WIN)