rebaseline_server: use just skpdiff, not Python Image Library

tools/skpdiff/SkDiffContext.h

Index: tools/skpdiff/SkDiffContext.h
diff --git a/tools/skpdiff/SkDiffContext.h b/tools/skpdiff/SkDiffContext.h
index c036c2ef6cd0c169f1a99a38319af124aff9fdcc..996737f2eed6e3ac1ce89411c8fde4b4e9e4aa02 100644
--- a/tools/skpdiff/SkDiffContext.h
+++ b/tools/skpdiff/SkDiffContext.h
@@ -28,10 +28,28 @@ public:
     void setThreadCount(int threadCount) { fThreadCount = threadCount; }
 
     /**
-     * Creates the directory if it does not exist and uses it to store differences
-     * between images.
+     * Sets the directory within which to store alphaMasks (images that
+     * are transparent for each pixel that differs between baseline and test).
+     *
+     * If the directory does not exist yet, it will be created.
+     */
+    void setAlphaMaskDir(const SkString& directory);
+
+    /**
+     * Sets the directory within which to store rgbDiffs (images showing the
+     * per-channel difference between baseline and test at each pixel).
+     *
+     * If the directory does not exist yet, it will be created.
+     */
+    void setRgbDiffDir(const SkString& directory);
+
+    /**
+     * Sets the directory within which to store whiteDiffs (images showing white
+     * for each pixel that differs between baseline and test).
+     *
+     * If the directory does not exist yet, it will be created.
      */
-    void setDifferenceDir(const SkString& directory);
+    void setWhiteDiffDir(const SkString& directory);
 
     /**
      * Sets the differs to be used in each diff. Already started diffs will not retroactively use
@@ -74,6 +92,14 @@ public:
      *    "differencePath" : (optional) string containing the path to an alpha
      *                       mask of the pixel difference between the baseline
      *                       and test images
+     *                       TODO(epoger): consider renaming this "alphaMaskPath"
+     *                       to distinguish from other difference types?
+     *    "rgbDiffPath"    : (optional) string containing the path to a bitmap
+     *                       showing per-channel differences between the
+     *                       baseline and test images at each pixel
+     *    "whiteDiffPath"  : (optional) string containing the path to a bitmap
+     *                       showing every pixel that differs between the
+     *                       baseline and test images as white
      *
      * They also have an array named "diffs" with each element being one diff record for the two
      * images indicated in the above field.
@@ -117,10 +143,21 @@ private:
     };
 
     struct DiffRecord {
+        // TODO(djsollen): Some of these fields are required, while others are optional
+        // (e.g., fRgbDiffPath is only filled in if SkDifferentPixelsMetric
+        // was run).  Figure out a way to note that.  See http://skbug.com/2712
+        // ('allow skpdiff to report different sets of result fields for
+        // different comparison algorithms')
         SkString           fCommonName;
-        SkString           fDifferencePath;
+        SkString           fAlphaMaskPath;
+        SkString           fRgbDiffPath;
+        SkString           fWhiteDiffPath;
         SkString           fBaselinePath;
         SkString               fTestPath;
+        SkISize                    fSize;
+        int                  fMaxRedDiff;
+        int                fMaxGreenDiff;
+        int                 fMaxBlueDiff;
         SkTArray<DiffData>        fDiffs;
     };
 
@@ -137,7 +174,9 @@ private:
     int fDifferCount;
     int fThreadCount;
 
-    SkString fDifferenceDir;
+    SkString fAlphaMaskDir;
+    SkString fRgbDiffDir;
+    SkString fWhiteDiffDir;
 };
 
 #endif