gpu: Cache results of GetShaderPrecisionFormat client-side

gpu/command_buffer/client/gles2_implementation.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "../client/gles2_implementation.h"
 
 #include <algorithm>
 #include <map>
@@ skipping 1923 matching lines @@
       << GLES2Util::GetStringShaderType(shadertype) << ", "
       << GLES2Util::GetStringShaderPrecision(precisiontype) << ", "
       << static_cast<const void*>(range) << ", "
       << static_cast<const void*>(precision) << ", ");
   TRACE_EVENT0("gpu", "GLES2::GetShaderPrecisionFormat");
   typedef cmds::GetShaderPrecisionFormat::Result Result;
   Result* result = GetResultAs<Result*>();
   if (!result) {
     return;
   }
-  result->success = false;
-  helper_->GetShaderPrecisionFormat(
-    shadertype, precisiontype, GetResultShmId(), GetResultShmOffset());
-  WaitForCmd();
+
+  ShaderPrecisionCacheKey key(shadertype, precisiontype);
+  ShaderPrecisionCacheMap::iterator i = shader_precision_cache_.find(key);
+  if (i != shader_precision_cache_.end()) {
+    *result = i->second;
+  } else {
+    result->success = false;
+    helper_->GetShaderPrecisionFormat(
+      shadertype, precisiontype, GetResultShmId(), GetResultShmOffset());
+    WaitForCmd();
+    if (result->success)
+      shader_precision_cache_[key] = *result;
+  }
+
   if (result->success) {
     if (range) {
       range[0] = result->min_range;
       range[1] = result->max_range;
       GPU_CLIENT_LOG("  min_range: " << range[0]);
       GPU_CLIENT_LOG("  min_range: " << range[1]);
     }
     if (precision) {
       precision[0] = result->precision;
       GPU_CLIENT_LOG("  min_range: " << precision[0]);
@@ skipping 1495 matching lines @@
   return helper_->InsertSyncPointCHROMIUM();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "../client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu