Reland of Extend CopyTextureCHROMIUM to more ES 3.0 texture formats.

gpu/command_buffer/tests/gl_test_utils.cc

Index: gpu/command_buffer/tests/gl_test_utils.cc
diff --git a/gpu/command_buffer/tests/gl_test_utils.cc b/gpu/command_buffer/tests/gl_test_utils.cc
index 5917bfe6c8e2d843fae1e39836fd388b85356e74..2a76cb9b23f99a259af54330df514e892f9b1fb8 100644
--- a/gpu/command_buffer/tests/gl_test_utils.cc
+++ b/gpu/command_buffer/tests/gl_test_utils.cc
@@ -209,16 +209,18 @@ bool GLTestHelper::CheckPixels(GLint x,
                                GLsizei width,
                                GLsizei height,
                                GLint tolerance,
-                               const uint8_t* color) {
+                               const uint8_t* color,
+                               int channel_count) {
   GLsizei size = width * height * 4;
   std::unique_ptr<uint8_t[]> pixels(new uint8_t[size]);
   memset(pixels.get(), kCheckClearValue, size);
   glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels.get());
   int bad_count = 0;
+  channel_count = channel_count > 4 ? 4 : channel_count;
   for (GLint yy = 0; yy < height; ++yy) {
     for (GLint xx = 0; xx < width; ++xx) {
       int offset = yy * width * 4 + xx * 4;
-      for (int jj = 0; jj < 4; ++jj) {
+      for (int jj = 0; jj < channel_count; ++jj) {
         uint8_t actual = pixels[offset + jj];
         uint8_t expected = color[jj];
         int diff = actual - expected;