add SkPixmap and external locking to bitmaps

src/core/SkPixelRef.cpp

Index: src/core/SkPixelRef.cpp
diff --git a/src/core/SkPixelRef.cpp b/src/core/SkPixelRef.cpp
index 20a8b34f067ff7eafc35759cb96b1b94de475a56..ec692fb1e44732b553c01d98eeeaba7833a350a8 100644
--- a/src/core/SkPixelRef.cpp
+++ b/src/core/SkPixelRef.cpp
@@ -199,6 +199,26 @@ void SkPixelRef::unlockPixels() {
     }
 }
 
+bool SkPixelRef::requestLock(const LockRequest& request, LockResult* result) {
+    SkASSERT(result);
+    if (request.fSize.isEmpty()) {
+        return false;
+    }
+
+    if (fPreLocked) {
+        result->fUnlockProc = NULL;
+        result->fUnlockContext = NULL;
+        result->fCTable = fRec.fColorTable;
+        result->fPixels = fRec.fPixels;
+        result->fRowBytes = fRec.fRowBytes;
+        result->fSize.set(fInfo.width(), fInfo.height());
+        return true;
+    } else {
+        SkAutoMutexAcquire  ac(*fMutex);
+        return this->onRequestLock(request, result);
+    }
+}
+
 bool SkPixelRef::lockPixelsAreWritable() const {
     return this->onLockPixelsAreWritable();
 }
@@ -271,6 +291,8 @@ bool SkPixelRef::readPixels(SkBitmap* dst, const SkIRect* subset) {
     return this->onReadPixels(dst, subset);
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 bool SkPixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {
     return false;
 }
@@ -288,3 +310,22 @@ size_t SkPixelRef::getAllocatedSizeInBytes() const {
     return 0;
 }
 
+static void unlock_legacy_result(void* ctx) {
+    SkPixelRef* pr = (SkPixelRef*)ctx;
+    pr->unlockPixels();
+}
+
+bool SkPixelRef::onRequestLock(const LockRequest& request, LockResult* result) {
+    LockRec rec;
+    if (!this->onNewLockPixels(&rec)) {
+        return false;
+    }
+
+    result->fUnlockProc = unlock_legacy_result;
+    result->fUnlockContext = SkRef(this);
+    result->fCTable = rec.fColorTable;
+    result->fPixels = rec.fPixels;
+    result->fRowBytes = rec.fRowBytes;
+    result->fSize.set(fInfo.width(), fInfo.height());
+    return true;
+}