Prevent reported RenderViewImplTest LSan leaks.
Prevent reported RenderViewImplTest LSan leaks.

Add missing calls to ProcessPendingMessages() to a pair of
RenderViewImplTest unit tests. Not doing so would, with Oilpan enabled,
flakily hold on to the entire view of the test and report it as leaking
with LSan.

R=jochen
BUG=

Review URL: https://codereview.chromium.org/1495923002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#363196}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk