Fix gpu mipmap support on ChromeOS

ui/gl/gl_version_info.cc

Index: ui/gl/gl_version_info.cc
diff --git a/ui/gl/gl_version_info.cc b/ui/gl/gl_version_info.cc
index 31392527db15c7a34ecaefbb75146c0a253fbcd1..31a512fe0c359e6061a927b1b917e30ed866b4ec 100644
--- a/ui/gl/gl_version_info.cc
+++ b/ui/gl/gl_version_info.cc
@@ -45,6 +45,7 @@ GLVersionInfo::GLVersionInfo(const char* version_str,
 GLVersionInfo::GLVersionInfo()
     : is_es(false),
       is_angle(false),
+      is_mesa(false),
       major_version(0),
       minor_version(0),
       is_es2(false),
@@ -62,6 +63,8 @@ void GLVersionInfo::Initialize(const char* version_str,
   if (renderer_str) {
     is_angle = base::StartsWith(renderer_str, "ANGLE",
                                 base::CompareCase::SENSITIVE);
+    is_mesa = base::StartsWith(renderer_str, "Mesa",
+                               base::CompareCase::SENSITIVE);
   }
   is_desktop_core_profile =
       DesktopCoreCommonCheck(is_es, major_version, minor_version) &&