Revert "Improve handling of GrPixelConfig in GrBackendTex/RT ctors"

This reverts commit 7d2b16ad13fd3262c776ae75ae35da4ad69df690.

Reason for revert: Maybe breaking chrome?

Original change's description:
> Improve handling of GrPixelConfig in GrBackendTex/RT ctors
> 
> Make sure that no client facing code was relying on what we set as the
> default value for fConfig by making in kUnkown.
> 
> Bug: skia:
> Change-Id: Ie52ff08ba8deeacc16fe06eb0dd0c7292b2edf91
> Reviewed-on: https://skia-review.googlesource.com/114261
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,robertphillips@google.com

Change-Id: I91e190d72407f9c4bee93a031a557f740bb49b66
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/114423
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/tools/gpu/GrTest.cpp b/tools/gpu/GrTest.cpp
index dfb8c2d..e1a7924 100644
--- a/tools/gpu/GrTest.cpp
+++ b/tools/gpu/GrTest.cpp
@@ -56,32 +56,26 @@
 GrBackendTexture CreateBackendTexture(GrBackend backend, int width, int height,
                                       GrPixelConfig config, GrMipMapped mipMapped,
                                       GrBackendObject handle) {
-    GrBackendTexture beTex;
     switch (backend) {
 #ifdef SK_VULKAN
         case kVulkan_GrBackend: {
             GrVkImageInfo* vkInfo = (GrVkImageInfo*)(handle);
             SkASSERT((GrMipMapped::kYes == mipMapped) == (vkInfo->fLevelCount > 1));
-            beTex = GrBackendTexture(width, height, *vkInfo);
-            break;
+            return GrBackendTexture(width, height, *vkInfo);
         }
 #endif
         case kOpenGL_GrBackend: {
             GrGLTextureInfo* glInfo = (GrGLTextureInfo*)(handle);
             SkASSERT(glInfo->fFormat);
-            beTex = GrBackendTexture(width, height, mipMapped, *glInfo);
-            break;
+            return GrBackendTexture(width, height, mipMapped, *glInfo);
         }
         case kMock_GrBackend: {
             GrMockTextureInfo* mockInfo = (GrMockTextureInfo*)(handle);
-            beTex = GrBackendTexture(width, height, mipMapped, *mockInfo);
-            break;
+            return GrBackendTexture(width, height, mipMapped, *mockInfo);
         }
         default:
             return GrBackendTexture();
     }
-    beTex.setPixelConfig(config);
-    return beTex;
 }
 
 GrBackendFormat CreateBackendFormatFromTexture(const GrBackendTexture& tex) {
@@ -344,6 +338,16 @@
 
 //////////////////////////////////////////////////////////////////////////////
 
+GrPixelConfig GrBackendTexture::testingOnly_getPixelConfig() const {
+    return fConfig;
+}
+
+GrPixelConfig GrBackendRenderTarget::testingOnly_getPixelConfig() const {
+    return fConfig;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
 #define DRAW_OP_TEST_EXTERN(Op) \
     extern std::unique_ptr<GrDrawOp> Op##__Test(GrPaint&&, SkRandom*, GrContext*, GrFSAAType)
 #define DRAW_OP_TEST_ENTRY(Op) Op##__Test