Switch the about:gpu implementation from an about handler to dom_ui....

chrome/common/url_constants.h

Index: chrome/common/url_constants.h
===================================================================
--- chrome/common/url_constants.h	(revision 65555)
+++ chrome/common/url_constants.h	(working copy)
@@ -47,6 +47,7 @@
 extern const char kAboutCreditsURL[];
 extern const char kAboutDNSURL[];
 extern const char kAboutFlagsURL[];
+extern const char kAboutGpuURL[];
 extern const char kAboutGpuCrashURL[];
 extern const char kAboutGpuHangURL[];
 extern const char kAboutHangURL[];
@@ -105,6 +106,7 @@
 extern const char kChromeUIExtensionsHost[];
 extern const char kChromeUIFavIconHost[];
 extern const char kChromeUIFlagsHost[];
+extern const char kChromeUIGpuHost[];
 extern const char kChromeUIHistory2Host[];
 extern const char kChromeUIHistoryHost[];
 extern const char kChromeUIKeyboardHost[];
@@ -153,6 +155,9 @@
 extern const char kNetworkViewCacheURL[];
 extern const char kNetworkViewInternalsURL[];
 
+// GPU related URLs
+extern const char kGpuURL[];
+
 // Options sub-pages.
 extern const char kAdvancedOptionsSubPage[];
 extern const char kAutoFillSubPage[];