Optimize GLES2Util::ComputeDataSize using templates.

Use templates to determine the size of each element and the elements per
unit allowing ComputeDataSize to only use a single inlined CheckedNumeric
multiply with a compile-time constant.

The data size validation of glUniform calls was up to 12% of the GPU
process' CPU time on some WebGL applications, this lowers it to be less
than 0.1%.

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Ic6e5f975087308da9473918a9ef081c0b591fbb4
Reviewed-on: https://chromium-review.googlesource.com/559104Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485297}

gpu/command_buffer/build_gles2_cmd_buffer.py

@@ -7094,7 +7094,7 @@ TEST_P(%(test_name)s, %(name)sInvalidArgs%(arg_index)d_%(value_index)d) {
   def WriteGetDataSizeCode(self, func, f):
     """Overrriden from TypeHandler."""
     code = """  uint32_t data_size;
-  if (!GLES2Util::ComputeDataSize(1, sizeof(%s), %d, &data_size)) {
+  if (!GLES2Util::ComputeDataSize<%s, %d>(1, &data_size)) {
     return error::kOutOfBounds;
   }
 """
@@ -7392,7 +7392,7 @@ TEST_P(%(test_name)s, %(name)sInvalidArgs%(arg_index)d_%(value_index)d) {
     """Overrriden from TypeHandler."""
     code = """  uint32_t data_size = 0;
   if (count >= 0 &&
-      !GLES2Util::ComputeDataSize(count, sizeof(%s), %d, &data_size)) {
+      !GLES2Util::ComputeDataSize<%s, %d>(count, &data_size)) {
     return error::kOutOfBounds;
   }
 """

gpu/command_buffer/common/gles2_cmd_utils.cc

@@ -1820,22 +1820,6 @@ uint32_t GLES2Util::ConvertToSizedFormat(uint32_t format, uint32_t type) {
   return format;
 }
 
-// static
-bool GLES2Util::ComputeDataSize(uint32_t count,
-                                size_t size,
-                                unsigned int elements_per_unit,
-                                uint32_t* dst) {
-  uint32_t value;
-  if (!SafeMultiplyUint32(count, static_cast<uint32_t>(size), &value)) {
-    return false;
-  }
-  if (!SafeMultiplyUint32(value, elements_per_unit, &value)) {
-    return false;
-  }
-  *dst = value;
-  return true;
-}
-
 namespace {
 
 // GL context configuration attributes. Those in the 16-bit range are the same

gpu/command_buffer/common/gles2_cmd_utils.h

@@ -252,10 +252,12 @@ class GLES2_UTILS_EXPORT GLES2Util {
       uint32_t internal_format, uint32_t type, int* r, int* g, int* b, int* a);
 
   // Computes the data size for certain gl commands like glUniform.
-  static bool ComputeDataSize(uint32_t count,
-                              size_t size,
-                              unsigned int elements_per_unit,
-                              uint32_t* dst);
+  template <typename VALUE_TYPE, unsigned int ELEMENTS_PER_UNIT>
+  static bool ComputeDataSize(uint32_t count, uint32_t* dst) {
+    constexpr uint32_t element_size = sizeof(VALUE_TYPE) * ELEMENTS_PER_UNIT;
+    return base::CheckMul(count, element_size)
+        .template AssignIfValid<uint32_t>(dst);
+  }
 
 #include "gpu/command_buffer/common/gles2_cmd_utils_autogen.h"