cc: Fix uninitialized field in TextureMailbox

BUG=None

Review URL: https://chromiumcodereview.appspot.com/15826003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202044 0039d316-1c4b-4281-b951-d872f2087c98

cc/resources/texture_mailbox.cc

@@ -10,7 +10,8 @@
 namespace cc {
 
 TextureMailbox::TextureMailbox()
-    : sync_point_(0) {
+    : target_(GL_TEXTURE_2D),
+      sync_point_(0) {
 }
 
 TextureMailbox::TextureMailbox(