Revert "Revert "Revert "Revert of https://codereview.chromium.org/110593003/"""

src/core/SkPixelRef.cpp

Index: src/core/SkPixelRef.cpp
diff --git a/src/core/SkPixelRef.cpp b/src/core/SkPixelRef.cpp
index 8bf1f4eddf27d322fb51cbd7ba65f432846ffb67..10e1309c0b1af377268a0bdb30f4de2f9b61dee3 100644
--- a/src/core/SkPixelRef.cpp
+++ b/src/core/SkPixelRef.cpp
@@ -82,20 +82,19 @@ void SkPixelRef::setMutex(SkBaseMutex* mutex) {
 // just need a > 0 value, so pick a funny one to aid in debugging
 #define SKPIXELREF_PRELOCKED_LOCKCOUNT     123456789
 
-SkPixelRef::SkPixelRef(const SkImageInfo& info, SkBaseMutex* mutex) : fInfo(info) {
-    this->setMutex(mutex);
-    fPixels = NULL;
-    fColorTable = NULL; // we do not track ownership of this
+SkPixelRef::SkPixelRef(const SkImageInfo& info) : fInfo(info) {
+    this->setMutex(NULL);
+    fRec.zero();
     fLockCount = 0;
     this->needsNewGenID();
     fIsImmutable = false;
     fPreLocked = false;
 }
 
-SkPixelRef::SkPixelRef(const SkImageInfo& info) : fInfo(info) {
-    this->setMutex(NULL);
-    fPixels = NULL;
-    fColorTable = NULL; // we do not track ownership of this
+
+SkPixelRef::SkPixelRef(const SkImageInfo& info, SkBaseMutex* mutex) : fInfo(info) {
+    this->setMutex(mutex);
+    fRec.zero();
     fLockCount = 0;
     this->needsNewGenID();
     fIsImmutable = false;
@@ -113,8 +112,7 @@ SkPixelRef::SkPixelRef(SkFlattenableReadBuffer& buffer, SkBaseMutex* mutex)
         , fInfo(read_info(buffer))
 {
     this->setMutex(mutex);
-    fPixels = NULL;
-    fColorTable = NULL; // we do not track ownership of this
+    fRec.zero();
     fLockCount = 0;
     fIsImmutable = buffer.readBool();
     fGenerationID = buffer.readUInt();
@@ -138,13 +136,13 @@ void SkPixelRef::cloneGenID(const SkPixelRef& that) {
     that.fUniqueGenerationID = false;
 }
 
-// rowBytes will be respected when we land the onNewLockPixels CL
 void SkPixelRef::setPreLocked(void* pixels, size_t rowBytes, SkColorTable* ctable) {
 #ifndef SK_IGNORE_PIXELREF_SETPRELOCKED
     // only call me in your constructor, otherwise fLockCount tracking can get
     // out of sync.
-    fPixels = pixels;
-    fColorTable = ctable;
+    fRec.fPixels = pixels;
+    fRec.fColorTable = ctable;
+    fRec.fRowBytes = rowBytes;
     fLockCount = SKPIXELREF_PRELOCKED_LOCKCOUNT;
     fPreLocked = true;
 #endif
@@ -167,20 +165,30 @@ void SkPixelRef::flatten(SkFlattenableWriteBuffer& buffer) const {
     }
 }
 
-void SkPixelRef::lockPixels() {
+bool SkPixelRef::lockPixels(LockRec* rec) {
     SkASSERT(!fPreLocked || SKPIXELREF_PRELOCKED_LOCKCOUNT == fLockCount);
 
     if (!fPreLocked) {
         SkAutoMutexAcquire  ac(*fMutex);
 
         if (1 == ++fLockCount) {
-            fPixels = this->onLockPixels(&fColorTable);
-            // If onLockPixels failed, it will return NULL
-            if (NULL == fPixels) {
-                fColorTable = NULL;
+            SkASSERT(fRec.isZero());
+
+            LockRec rec;
+            if (!this->onNewLockPixels(&rec)) {
+                return false;
             }
+            SkASSERT(!rec.isZero());    // else why did onNewLock return true?
+            fRec = rec;
         }
     }
+    *rec = fRec;
+    return true;
+}
+
+bool SkPixelRef::lockPixels() {
+    LockRec rec;
+    return this->lockPixels(&rec);
 }
 
 void SkPixelRef::unlockPixels() {
@@ -192,12 +200,11 @@ void SkPixelRef::unlockPixels() {
         SkASSERT(fLockCount > 0);
         if (0 == --fLockCount) {
             // don't call onUnlockPixels unless onLockPixels succeeded
-            if (fPixels) {
+            if (fRec.fPixels) {
                 this->onUnlockPixels();
-                fPixels = NULL;
-                fColorTable = NULL;
+                fRec.zero();
             } else {
-                SkASSERT(NULL == fColorTable);
+                SkASSERT(fRec.isZero());
             }
         }
     }
@@ -279,6 +286,29 @@ size_t SkPixelRef::getAllocatedSizeInBytes() const {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#ifdef SK_SUPPORT_LEGACY_ONLOCKPIXELS
+
+void* SkPixelRef::onLockPixels(SkColorTable** ctable) {
+    return NULL;
+}
+
+bool SkPixelRef::onNewLockPixels(LockRec* rec) {
+    SkColorTable* ctable = NULL;    // for legacy clients who forget to set this
+    void* pixels = this->onLockPixels(&ctable);
+    if (!pixels) {
+        return false;
+    }
+
+    rec->fPixels = pixels;
+    rec->fColorTable = ctable;
+    rec->fRowBytes = 0; // callers don't currently need this (thank goodness)
+    return true;
+}
+
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+
 #ifdef SK_BUILD_FOR_ANDROID
 void SkPixelRef::globalRef(void* data) {
     this->ref();