Revert of implement readPixels and writePixels natively, w/o using the (deprecated)

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 9a277b05917fcfc0516d1fa6f40add5f20dc1d6d..c016d062abe1254d52da583ab7a301d38262d548 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -25,7 +25,6 @@
 #include "GrSoftwarePathRenderer.h"
 #include "GrStencilBuffer.h"
 #include "GrTextStrike.h"
-#include "SkGr.h"
 #include "SkRTConf.h"
 #include "SkRRect.h"
 #include "SkStrokeRec.h"
@@ -1260,14 +1259,53 @@
 
 #include "SkConfig8888.h"
 
-// toggles between RGBA and BGRA
-static SkColorType toggle_colortype32(SkColorType ct) {
-    if (kRGBA_8888_SkColorType == ct) {
-        return kBGRA_8888_SkColorType;
-    } else {
-        SkASSERT(kBGRA_8888_SkColorType == ct);
-        return kRGBA_8888_SkColorType;
-    }
+namespace {
+/**
+ * Converts a GrPixelConfig to a SkCanvas::Config8888. Only byte-per-channel
+ * formats are representable as Config8888 and so the function returns false
+ * if the GrPixelConfig has no equivalent Config8888.
+ */
+bool grconfig_to_config8888(GrPixelConfig config,
+                            bool unpremul,
+                            SkCanvas::Config8888* config8888) {
+    switch (config) {
+        case kRGBA_8888_GrPixelConfig:
+            if (unpremul) {
+                *config8888 = SkCanvas::kRGBA_Unpremul_Config8888;
+            } else {
+                *config8888 = SkCanvas::kRGBA_Premul_Config8888;
+            }
+            return true;
+        case kBGRA_8888_GrPixelConfig:
+            if (unpremul) {
+                *config8888 = SkCanvas::kBGRA_Unpremul_Config8888;
+            } else {
+                *config8888 = SkCanvas::kBGRA_Premul_Config8888;
+            }
+            return true;
+        default:
+            return false;
+    }
+}
+
+// It returns a configuration with where the byte position of the R & B components are swapped in
+// relation to the input config. This should only be called with the result of
+// grconfig_to_config8888 as it will fail for other configs.
+SkCanvas::Config8888 swap_config8888_red_and_blue(SkCanvas::Config8888 config8888) {
+    switch (config8888) {
+        case SkCanvas::kBGRA_Premul_Config8888:
+            return SkCanvas::kRGBA_Premul_Config8888;
+        case SkCanvas::kBGRA_Unpremul_Config8888:
+            return SkCanvas::kRGBA_Unpremul_Config8888;
+        case SkCanvas::kRGBA_Premul_Config8888:
+            return SkCanvas::kBGRA_Premul_Config8888;
+        case SkCanvas::kRGBA_Unpremul_Config8888:
+            return SkCanvas::kBGRA_Unpremul_Config8888;
+        default:
+            GrCrash("Unexpected input");
+            return SkCanvas::kBGRA_Unpremul_Config8888;;
+    }
+}
 }
 
 bool GrContext::readRenderTargetPixels(GrRenderTarget* target,
@@ -1394,21 +1432,22 @@
     }
     // Perform any conversions we weren't able to perform using a scratch texture.
     if (unpremul || swapRAndB) {
-        SkDstPixelInfo dstPI;
-        if (!GrPixelConfig2ColorType(dstConfig, &dstPI.fColorType)) {
-            return false;
-        }
-        dstPI.fAlphaType = kUnpremul_SkAlphaType;
-        dstPI.fPixels = buffer;
-        dstPI.fRowBytes = rowBytes;
-
-        SkSrcPixelInfo srcPI;
-        srcPI.fColorType = swapRAndB ? toggle_colortype32(dstPI.fColorType) : dstPI.fColorType;
-        srcPI.fAlphaType = kPremul_SkAlphaType;
-        srcPI.fPixels = buffer;
-        srcPI.fRowBytes = rowBytes;
-
-        return srcPI.convertPixelsTo(&dstPI, width, height);
+        // These are initialized to suppress a warning
+        SkCanvas::Config8888 srcC8888 = SkCanvas::kNative_Premul_Config8888;
+        SkCanvas::Config8888 dstC8888 = SkCanvas::kNative_Premul_Config8888;
+
+        SkDEBUGCODE(bool c8888IsValid =) grconfig_to_config8888(dstConfig, false, &srcC8888);
+        grconfig_to_config8888(dstConfig, unpremul, &dstC8888);
+
+        if (swapRAndB) {
+            SkASSERT(c8888IsValid); // we should only do r/b swap on 8888 configs
+            srcC8888 = swap_config8888_red_and_blue(srcC8888);
+        }
+        SkASSERT(c8888IsValid);
+        uint32_t* b32 = reinterpret_cast<uint32_t*>(buffer);
+        SkConvertConfig8888Pixels(b32, rowBytes, dstC8888,
+                                  b32, rowBytes, srcC8888,
+                                  width, height);
     }
     return true;
 }
@@ -1528,24 +1567,18 @@
         effect.reset(this->createUPMToPMEffect(texture, swapRAndB, textureMatrix));
         // handle the unpremul step on the CPU if we couldn't create an effect to do it.
         if (NULL == effect) {
-            SkSrcPixelInfo srcPI;
-            if (!GrPixelConfig2ColorType(srcConfig, &srcPI.fColorType)) {
-                return false;
-            }
-            srcPI.fAlphaType = kUnpremul_SkAlphaType;
-            srcPI.fPixels = buffer;
-            srcPI.fRowBytes = rowBytes;
-
-            SkDstPixelInfo dstPI;
-            dstPI.fColorType = srcPI.fColorType;
-            dstPI.fAlphaType = kPremul_SkAlphaType;
-            dstPI.fPixels = tmpPixels.get();
-            dstPI.fRowBytes = 4 * width;
-
-            if (!srcPI.convertPixelsTo(&dstPI, width, height)) {
-                return false;
-            }
-
+            SkCanvas::Config8888 srcConfig8888, dstConfig8888;
+            SkDEBUGCODE(bool success = )
+            grconfig_to_config8888(srcConfig, true, &srcConfig8888);
+            SkASSERT(success);
+            SkDEBUGCODE(success = )
+            grconfig_to_config8888(srcConfig, false, &dstConfig8888);
+            SkASSERT(success);
+            const uint32_t* src = reinterpret_cast<const uint32_t*>(buffer);
+            tmpPixels.reset(width * height);
+            SkConvertConfig8888Pixels(tmpPixels.get(), 4 * width, dstConfig8888,
+                                      src, rowBytes, srcConfig8888,
+                                      width, height);
             buffer = tmpPixels.get();
             rowBytes = 4 * width;
         }