[MemSherrif] Uninitialized Read

BUG=463204
TBR=reed@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/969073002

Cr-Commit-Position: refs/heads/master@{#318760}

tools/valgrind/drmemory/suppressions.txt

@@ -742,3 +742,11 @@ drmemorylib.dll!replace_operator_delete
 *!content::ContentMainRunnerImpl::Run
 *!content::ContentMain
 *!content::LaunchTests
+
+UNINITIALIZED READ
+name=http://crbug.com/463204
+skia.dll!_ltod3
+skia.dll!SkPaint::measure_text
+skia.dll!SkPaint::measureText
+content.dll!content::DoPreSandboxWarmupForTypeface
+content.dll!content::`anonymous namespace'::WarmupDirectWrite