If under stack pressure, do not enable eager stack use.

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef StackFrameDepth_h
 #define StackFrameDepth_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/Assertions.h"
@@ skipping 16 matching lines @@
         // all the ABIs currently supported do.
         //
         // A unit test checks that the assumption holds for a target
         // (HeapTest.StackGrowthDirection.)
         return currentStackFrame() > s_stackFrameLimit;
     }
 
     static void enableStackLimit();
     static void disableStackLimit()
     {
         s_stackFrameLimit = 0;

[sof, 2016/03/10 13:43:13]

Using 0 as the disabled limit value is strictly speaking unsafe, as it makes
isSafeToRecurse() always return true. Will address separately.

 #if ENABLE(ASSERT)
         s_isEnabled = false;
 #endif
     }
 
 #if ENABLE(ASSERT)
     inline static bool isEnabled() { return s_isEnabled; }
     inline static bool isAcceptableStackUse()
     {
         // ASan adds extra stack usage leading to too noisy asserts.
@@ skipping 49 matching lines @@
 #endif
 };
 
 class StackFrameDepthScope {
     STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(StackFrameDepthScope);
 public:
     StackFrameDepthScope()
     {
         StackFrameDepth::enableStackLimit();
-        ASSERT(StackFrameDepth::isSafeToRecurse());
+        // Enabled unless under stack pressure.
+        ASSERT(StackFrameDepth::isSafeToRecurse() || !StackFrameDepth::isEnabled());
     }
 
     ~StackFrameDepthScope()
     {
         StackFrameDepth::disableStackLimit();
     }
 };
 
 } // namespace blink
 
 #endif // StackFrameDepth_h