Remove kImageIsImmutable_Flag.

src/core/SkBitmap.cpp

Index: src/core/SkBitmap.cpp
diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index 651152e703bd5c2e0bf9c31b6f97f9d33abba532..7bf6d2433d2cbc2e45da4b4d8149fb45679c94b8 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -486,15 +486,12 @@ bool SkBitmap::copyPixelsTo(void* const dst, size_t dstSize,
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkBitmap::isImmutable() const {
-    return fPixelRef ? fPixelRef->isImmutable() :
-        fFlags & kImageIsImmutable_Flag;
+    return fPixelRef ? fPixelRef->isImmutable() : false;
 }
 
 void SkBitmap::setImmutable() {
     if (fPixelRef) {
         fPixelRef->setImmutable();
-    } else {
-        fFlags |= kImageIsImmutable_Flag;
     }
 }
 
@@ -1317,7 +1314,7 @@ void SkBitmap::validate() const {
     }
 
     SkASSERT(fInfo.validRowBytes(fRowBytes));
-    uint8_t allFlags = kImageIsOpaque_Flag | kImageIsVolatile_Flag | kImageIsImmutable_Flag;
+    uint8_t allFlags = kImageIsOpaque_Flag | kImageIsVolatile_Flag;
 #ifdef SK_BUILD_FOR_ANDROID
     allFlags |= kHasHardwareMipMap_Flag;
 #endif