Revert of Add compositor support for half-float RGBA buffers and textures

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index 20945540784af870e841cec7cc708996364183e8..7bf636b1d271bc2212ba0450856dc04ceb12aca8 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -86,9 +86,6 @@
     case BGRA_8888:
       storage_format = GL_BGRA8_EXT;
       break;
-    case RGBA_F16:
-      storage_format = GL_RGBA16F_EXT;
-      break;
     case RGBA_4444:
     case ALPHA_8:
     case LUMINANCE_8:
@@ -106,7 +103,6 @@
 bool IsFormatSupportedForStorage(ResourceFormat format, bool use_bgra) {
   switch (format) {
     case RGBA_8888:
-    case RGBA_F16:
       return true;
     case BGRA_8888:
       return use_bgra;
@@ -130,8 +126,6 @@
       return kBGRA_8888_GrPixelConfig;
     case RGBA_4444:
       return kRGBA_4444_GrPixelConfig;
-    case RGBA_F16:
-      return kRGBA_half_GrPixelConfig;
     default:
       break;
   }
@@ -543,11 +537,6 @@
       return caps.texture_rg;
     case LUMINANCE_F16:
       return caps.texture_half_float_linear;
-    case RGBA_F16:
-      // TODO(ccameron): This will always return false on pixel tests, which
-      // makes it un-test-able until we upgrade Mesa.
-      // https://crbug.com/687720
-      return caps.texture_half_float_linear && caps.color_buffer_float;
   }
 
   NOTREACHED();
@@ -587,8 +576,8 @@
   DCHECK(!size.IsEmpty());
   switch (settings_.default_resource_type) {
     case RESOURCE_TYPE_GPU_MEMORY_BUFFER:
-      // GPU memory buffers don't support LUMINANCE_F16 or RGBA_F16 yet.
-      if (format != LUMINANCE_F16 && format != RGBA_F16) {
+      // GPU memory buffers don't support LUMINANCE_F16.
+      if (format != LUMINANCE_F16) {
         return CreateGLTexture(
             size, hint, RESOURCE_TYPE_GPU_MEMORY_BUFFER, format,
             gfx::BufferUsage::GPU_READ_CPU_READ_WRITE, color_space);