Fix debugger's overdraw color filter

src/utils/debugger/SkDebugCanvas.cpp

Index: src/utils/debugger/SkDebugCanvas.cpp
diff --git a/src/utils/debugger/SkDebugCanvas.cpp b/src/utils/debugger/SkDebugCanvas.cpp
index aed87cc22120e4e03f3e6af004ddebe8c9f638b5..1faa015b364a4ca7a4d3f32d20ca941c9f68f34c 100644
--- a/src/utils/debugger/SkDebugCanvas.cpp
+++ b/src/utils/debugger/SkDebugCanvas.cpp
@@ -105,14 +105,22 @@ public:
             SkPackARGB32(0xFF, 255,  50, 0),
             SkPackARGB32(0xFF, 255,  0, 0)
         };
-
-        for (size_t i = 0; i < SK_ARRAY_COUNT(gTable)-1; ++i) {
-            if (gTable[i] == dst) {
-                return gTable[i+1];
-            }
-        }
-
-        return gTable[SK_ARRAY_COUNT(gTable)-1];
+ 
+
+        int idx;
+        if (SkColorGetR(dst) < 64) { // 0
+            idx = 0;
+        } else if (SkColorGetG(dst) < 25) { // 10
+            idx = 9;  // cap at 9 for upcoming increment
+        } else if ((SkColorGetB(dst)+21)/42 > 0) { // 1-6
+            idx = 7 - (SkColorGetB(dst)+21)/42;
+        } else { // 7-9
+            idx = 10 - (SkColorGetG(dst)+22)/45;
+        }
+        ++idx;
+        SkASSERT(idx < (int)SK_ARRAY_COUNT(gTable));
+
+        return gTable[idx];
     }
 
     Factory getFactory() const SK_OVERRIDE { return NULL; }
@@ -133,6 +141,7 @@ public:
 
     bool filter(SkPaint* p, Type) SK_OVERRIDE {
         p->setXfermode(fXferMode);
+        p->setAntiAlias(false);
         return true;
     }