DisplayItemClient: avoid hash table temporaries when iterating.

third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp
index 009cce510506c3b0f72cf782b69ec0114cacacaf..1748aa25f4cb352d0356e2a739e5276ed660aa05 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemClient.cpp
@@ -23,7 +23,7 @@ HashMap<const void*, HashMap<const DisplayItemClient*, String>>*
 
 DisplayItemClient::DisplayItemClient() {
   if (displayItemClientsShouldKeepAlive) {
-    for (auto item : *displayItemClientsShouldKeepAlive)
+    for (const auto& item : *displayItemClientsShouldKeepAlive)
       CHECK(!item.value.contains(this));
   }
   if (!liveDisplayItemClients)
@@ -33,7 +33,7 @@ DisplayItemClient::DisplayItemClient() {
 
 DisplayItemClient::~DisplayItemClient() {
   if (displayItemClientsShouldKeepAlive) {
-    for (auto& item : *displayItemClientsShouldKeepAlive) {
+    for (const auto& item : *displayItemClientsShouldKeepAlive) {
       CHECK(!item.value.contains(this))
           << "Short-lived DisplayItemClient: " << item.value.get(this)
           << ". See crbug.com/609218.";