Create swizzle table inside of glsl caps

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 1d25a2ca2f47eba5fcf1d4362387f9467983b1c4..389690fab84b4728b75b92291d14242f1ae14fc6 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -8,6 +8,7 @@
 
 #include "GrGLCaps.h"
 
+#include "GrContextOptions.h"
 #include "GrGLContext.h"
 #include "glsl/GrGLSLCaps.h"
 #include "SkTSearch.h"
@@ -491,6 +492,8 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
     this->initConfigTexturableTable(ctxInfo, gli, srgbSupport);
     this->initConfigRenderableTable(ctxInfo, srgbSupport);
     this->initShaderPrecisionTable(ctxInfo, gli, glslCaps);
+    // Requires fTexutreSwizzleSupport and fTextureRedSupport to be set before this point.
+    this->initConfigSwizzleTable(glslCaps);
 
     this->applyOptionsOverrides(contextOptions);
     glslCaps->applyOptionsOverrides(contextOptions);
@@ -1280,6 +1283,36 @@ void GrGLCaps::initShaderPrecisionTable(const GrGLContextInfo& ctxInfo,
     }
 }
 
+void GrGLCaps::initConfigSwizzleTable(GrGLSLCaps* glslCaps) {
+    glslCaps->fMustSwizzleInShader = !this->textureSwizzleSupport();
 
+    glslCaps->fConfigSwizzle[kUnknown_GrPixelConfig] = nullptr;
+    if (fTextureRedSupport) {
+        glslCaps->fConfigSwizzle[kAlpha_8_GrPixelConfig] = "rrrr";
+        glslCaps->fConfigSwizzle[kAlpha_half_GrPixelConfig] = "rrrr";
+    } else {
+        glslCaps->fConfigSwizzle[kAlpha_8_GrPixelConfig] = "aaaa";
+        glslCaps->fConfigSwizzle[kAlpha_half_GrPixelConfig] = "aaaa";
+    }
+    glslCaps->fConfigSwizzle[kIndex_8_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kRGB_565_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kRGBA_4444_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kRGBA_8888_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kBGRA_8888_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kSRGBA_8888_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kETC1_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kLATC_GrPixelConfig] = "rrrr";
+    glslCaps->fConfigSwizzle[kR11_EAC_GrPixelConfig] = "rrrr";
+    glslCaps->fConfigSwizzle[kASTC_12x12_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kRGBA_float_GrPixelConfig] = "rgba";
+    glslCaps->fConfigSwizzle[kRGBA_half_GrPixelConfig] = "rgba";
+
+}
+
+void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
+    if (options.fUseShaderSwizzling) {
+        fTextureSwizzleSupport = false;
+    }
+}