[oilpan] StackFrameDepth: Adjust stack room size

Latest clang rolls require a bit more stack space when calling through
the eager marking visitors.

Bug: chromium:807994
Change-Id: I5bb2a80fdca7f5d536fd965a9cd6151e81573f9a
Reviewed-on: https://chromium-review.googlesource.com/922206Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537255}

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

@@ -45,7 +45,10 @@ void StackFrameDepth::EnableStackLimit() {
     return;
   }
 
-  static const int kStackRoomSize = 1024;
+  // Adjust the following when running out of stack space in between turns of
+  // checking |IsSafeToRecurse()|. The required room size depends on the actions
+  // performed between turns and how well compiler optimizations apply.
+  static const int kStackRoomSize = 4096;
 
   Address stack_base = reinterpret_cast<Address>(WTF::GetStackStart());
   CHECK_GT(stack_size, static_cast<const size_t>(kStackRoomSize));