fix size_t/int warnings in pictures

src/core/SkMatrixClipStateMgr.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkMatrixClipStateMgr_DEFINED
 #define SkMatrixClipStateMgr_DEFINED
 
 #include "SkCanvas.h"
@@ skipping 350 matching lines @@
     SkTDArray<SkMatrix> fMatrixDict;
 
     SkTDArray<SkRegion*> fRegionDict;
 
     // The MCStateID of the state currently in effect in the byte stream. 0 if none.
     int32_t          fCurOpenStateID;
     // The skip offsets for the current open state. These are the locations in the
     // skp that must be filled in when the current open state is closed. These are
     // here rather then distributed across the MatrixClipState's because saveLayers
     // can cause MC states to be nested.
-    SkTDArray<int32_t>  *fSkipOffsets;
+    SkTDArray<int32_t>  *fSkipOffsets;  // TODO: should we store u32 or size_t instead?
 
     SkDEBUGCODE(void validate();)
 
     int MCStackPush(SkCanvas::SaveFlags flags);
 
-    void addClipOffset(int offset) {
+    void addClipOffset(size_t offset) {
         SkASSERT(NULL != fSkipOffsets);
         SkASSERT(kIdentityWideOpenStateID != fCurOpenStateID);
         SkASSERT(fCurMCState->fHasOpen);
         SkASSERT(!fCurMCState->fIsSaveLayer);
 
-        *fSkipOffsets->append() = offset;
+        *fSkipOffsets->append() = SkToS32(offset);
     }
 
     void writeDeltaMat(int currentMatID, int desiredMatID);
     static int32_t   NewMCStateID();
 
     int addRegionToDict(const SkRegion& region);
     const SkRegion* lookupRegion(int index) {
         SkASSERT(index >= 0 && index < fRegionDict.count());
         return fRegionDict[index];
     }
@@ skipping 11 matching lines @@
 #ifdef SK_DEBUG
     int fActualDepth;
 #endif
 
     // save layers are nested within a specific MC state. This stack tracks
     // the nesting MC state's ID as save layers are pushed and popped.
     SkTDArray<int> fStateIDStack;
 };
 
 #endif