Fix C4334 (32-bit shift converted to 64-bit) warnings

third_party/WebKit/Source/platform/heap/HeapPage.cpp

Index: third_party/WebKit/Source/platform/heap/HeapPage.cpp
diff --git a/third_party/WebKit/Source/platform/heap/HeapPage.cpp b/third_party/WebKit/Source/platform/heap/HeapPage.cpp
index c8fa6c0aad25fadbf1ed0dd77b4d216743b4343a..f994e7e2152c18e951afe099783d42f4aad78e61 100644
--- a/third_party/WebKit/Source/platform/heap/HeapPage.cpp
+++ b/third_party/WebKit/Source/platform/heap/HeapPage.cpp
@@ -735,7 +735,7 @@ Address NormalPageArena::allocateFromFreeList(size_t allocationSize, size_t gcIn
     // off as a large a free block as possible in one go; a block that will
     // service this block and let following allocations be serviced quickly
     // by bump allocation.
-    size_t bucketSize = 1 << m_freeList.m_biggestFreeListIndex;
+    size_t bucketSize = static_cast<size_t>(1) << m_freeList.m_biggestFreeListIndex;
     int index = m_freeList.m_biggestFreeListIndex;
     for (; index > 0; --index, bucketSize >>= 1) {
         FreeListEntry* entry = m_freeList.m_freeLists[index];