Checking structure sizes before reading them from memory to avoid overflowing the buffer's stream.

src/core/SkMatrix.cpp

Index: src/core/SkMatrix.cpp
diff --git a/src/core/SkMatrix.cpp b/src/core/SkMatrix.cpp
index 5bcb35b298874088004f5c39fba7133e85a0c323..e8d0b73468fff2a0ae59e35e79da2f1bb4fe01c0 100644
--- a/src/core/SkMatrix.cpp
+++ b/src/core/SkMatrix.cpp
@@ -1921,20 +1921,28 @@ const SkMatrix& SkMatrix::InvalidMatrix() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+uint32_t SkMatrix::sizeInMemory() const {
+    return SizeToRead(); // This is a constant for SkMatrix
+}
+
+uint32_t SkMatrix::SizeToRead() {
+    return 9 * sizeof(SkScalar);
+}
+
 uint32_t SkMatrix::writeToMemory(void* buffer) const {
     // TODO write less for simple matrices
     if (buffer) {
-        memcpy(buffer, fMat, 9 * sizeof(SkScalar));
+        memcpy(buffer, fMat, sizeInMemory());
     }
-    return 9 * sizeof(SkScalar);
+    return sizeInMemory();
 }
 
 uint32_t SkMatrix::readFromMemory(const void* buffer) {
     if (buffer) {
-        memcpy(fMat, buffer, 9 * sizeof(SkScalar));
+        memcpy(fMat, buffer, SizeToRead());
         this->setTypeMask(kUnknown_Mask);
     }
-    return 9 * sizeof(SkScalar);
+    return sizeInMemory();
 }
 
 #ifdef SK_DEVELOPER