cc: Use highp precision for texture coords if available and needed

cc/debug/fake_web_graphics_context_3d.cc

Index: cc/debug/fake_web_graphics_context_3d.cc
diff --git a/cc/debug/fake_web_graphics_context_3d.cc b/cc/debug/fake_web_graphics_context_3d.cc
index 0f5325586f79dca5554a45ae6df7672664632c17..ec2bbed549e25a785490ef31b31ca507c95c82f9 100644
--- a/cc/debug/fake_web_graphics_context_3d.cc
+++ b/cc/debug/fake_web_graphics_context_3d.cc
@@ -4,6 +4,7 @@
 
 #include "cc/debug/fake_web_graphics_context_3d.h"
 
+#include "base/logging.h"
 #include "third_party/khronos/GLES2/gl2.h"
 
 using WebKit::WGC3Dboolean;
@@ -152,6 +153,45 @@ WebKit::WebString FakeWebGraphicsContext3D::getShaderInfoLog(
   return WebKit::WebString();
 }
 
+void FakeWebGraphicsContext3D::getShaderPrecisionFormat(
+    WebKit::WGC3Denum shadertype,
+    WebKit::WGC3Denum precisiontype,
+    WebKit::WGC3Dint* range,
+    WebKit::WGC3Dint* precision) {
+  // Return the minimum precision requirements of the GLES specificatin.
+  switch (precisiontype) {
+    case GL_LOW_INT:
+      range[0] = 8;
+      range[1] = 8;
+      *precision = 0;
+    case GL_MEDIUM_INT:
+      range[0] = 10;
+      range[1] = 10;
+      *precision = 0;
+    case GL_HIGH_INT:
+      range[0] = 16;
+      range[1] = 16;
+      *precision = 0;
+      break;
+    case GL_LOW_FLOAT:
+      range[0] = 8;
+      range[1] = 8;
+      *precision = 8;
+    case GL_MEDIUM_FLOAT:
+      range[0] = 14;
+      range[1] = 14;
+      *precision = 10;
+    case GL_HIGH_FLOAT:
+      range[0] = 62;
+      range[1] = 62;
+      *precision = 16;
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
 WebKit::WebString FakeWebGraphicsContext3D::getShaderSource(
     WebGLId shader) {
   return WebKit::WebString();