Revert of Move copy-surface-as-draw fallback to GrGLGpu. (patchset #12 id:220001 of https://codereview.chromium.org/1144433002/)

Reason for revert:
Many GMs changed, some totally busted.

Original issue's description:
> Move copy-surface-as-draw fallback to GrGLGpu.
>
> Committed: https://skia.googlesource.com/skia/+/5df6fee929823f50c55cc50f7c882a309c1b1de9

TBR=joshualitt@google.com,egdaniel@google.com,bsalomon@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1142003003

1 files changed, 23 insertions, 3 deletions

diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
index afb0718cbd..044752f7a5 100644
--- a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
@@ -15,6 +15,26 @@
 const char* GrGLFragmentShaderBuilder::kDstCopyColorName = "_dstColor";
 static const char* declared_color_output_name() { return "fsColorOut"; }
 static const char* dual_source_output_name() { return "dualSourceOut"; }
+static void append_default_precision_qualifier(GrSLPrecision p,
+                                               GrGLStandard standard,
+                                               SkString* str) {
+    // Desktop GLSL has added precision qualifiers but they don't do anything.
+    if (kGLES_GrGLStandard == standard) {
+        switch (p) {
+            case kHigh_GrSLPrecision:
+                str->append("precision highp float;\n");
+                break;
+            case kMedium_GrSLPrecision:
+                str->append("precision mediump float;\n");
+                break;
+            case kLow_GrSLPrecision:
+                str->append("precision lowp float;\n");
+                break;
+            default:
+                SkFAIL("Unknown precision value.");
+        }
+    }
+}
 
 static const char* specific_layout_qualifier_name(GrBlendEquation equation) {
     SkASSERT(GrBlendEquationIsAdvanced(equation));
@@ -250,9 +270,9 @@ bool GrGLFragmentShaderBuilder::compileAndAttachShaders(GrGLuint programId,
                                                         SkTDArray<GrGLuint>* shaderIds) {
     GrGLGpu* gpu = fProgramBuilder->gpu();
     this->versionDecl() = GrGetGLSLVersionDecl(gpu->ctxInfo());
-    GrGLSLAppendDefaultFloatPrecisionDeclaration(kDefault_GrSLPrecision,
-                                                 gpu->glStandard(),
-                                                 &this->precisionQualifier());
+    append_default_precision_qualifier(kDefault_GrSLPrecision,
+                                       gpu->glStandard(),
+                                       &this->precisionQualifier());
     this->compileAndAppendLayoutQualifiers();
     fProgramBuilder->appendUniformDecls(GrGLProgramBuilder::kFragment_Visibility,
                                         &this->uniforms());