Allow HW accleration to be activated on demand.

This CL adds a debugging preference that allows developers to
enable/disable Open GL rendering on demand. The setting change
does not take effect until the browser is restarted.

bug: 3185844
Change-Id: Ifcf5a7b7d4ddbf02a649a28c4f462e2da3f34bb6
diff --git a/res/values/strings.xml b/res/values/strings.xml
index a6ad15e..d724085 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -520,6 +520,8 @@
     <!-- Do not tranlsate.  Development option -->
     <string name="pref_development_nav_dump" translatable="false">Enable nav cache dump</string>
     <!-- Do not tranlsate.  Development option -->
+    <string name="pref_development_hardware_accel" translatable="false">Enable OpenGL Rendering</string>
+    <!-- Do not tranlsate.  Development option -->
     <string name="js_engine_flags" translatable="false">Set JS flags</string>
     <!-- Do not tranlsate.  Development option -->
     <string name="pref_development_uastring" translatable="false">UAString</string>