V8: Add API to report OOM to embedder.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 4031769904c7fff2a339a783f5f1d7f981f78157..041375c1fcb0e8f61f004c5b6c81c4b22718e436 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -243,7 +243,7 @@ void i::FatalProcessOutOfMemory(const char* location) {
 
 
 // When V8 cannot allocated memory FatalProcessOutOfMemory is called.
-// The default fatal error handler is called and execution is stopped.
+// The default OOM error handler is called and execution is stopped.
 void i::V8::FatalProcessOutOfMemory(const char* location, bool is_heap_oom) {
   i::Isolate* isolate = i::Isolate::Current();
   char last_few_messages[Heap::kTraceRingBufferSize + 1];
@@ -306,9 +306,7 @@ void i::V8::FatalProcessOutOfMemory(const char* location, bool is_heap_oom) {
     PrintF("\n<--- Last few GCs --->\n%s\n", first_newline);
     PrintF("\n<--- JS stacktrace --->\n%s\n", js_stacktrace);
   }
-  Utils::ApiCheck(false, location, is_heap_oom
-                  ? "Allocation failed - JavaScript heap out of memory"
-                  : "Allocation failed - process out of memory");
+  Utils::ReportOOMFailure(location, is_heap_oom);
   // If the fatal error handler returns, we stop execution.
   FATAL("API fatal error handler returned after process out of memory");
 }
@@ -327,6 +325,18 @@ void Utils::ReportApiFailure(const char* location, const char* message) {
   isolate->SignalFatalError();
 }
 
+void Utils::ReportOOMFailure(const char* location, bool is_heap_oom) {
+  i::Isolate* isolate = i::Isolate::Current();
+  OOMErrorCallback callback = isolate->oom_behavior();
+  if (callback == nullptr) {

[Will Harris, 2016/07/12 15:46:10]

This will change the signature of OOM errors in v8 until blink can be updated to
call the SetOOMErrorHandler function (see
https://codereview.chromium.org/2130293003/) - but the blink side can't be
committed until this lands. It's probably okay to have this inconsistency for a
short period.

[Hannes Payer (out of office), 2016/07/13 09:21:11]

After landing 2130293003 the signature will change again. Why don't we keep the
current signature until then. We shouldn't change it too often because
Chromecrash, Clusterfuzz, etc. will think that a new crasher showed up.

[Will Harris, 2016/07/13 20:09:45]

now it will fall back to previous behavior if the oom handler is not set.

+    base::OS::PrintError("\n#\n# Fatal %s OOM in %s\n#\n\n",
+                         is_heap_oom ? "javascript" : "process", location);
+    base::OS::Abort();
+  } else {
+    callback(location, is_heap_oom);
+  }
+  isolate->SignalFatalError();
+}
 
 static inline bool IsExecutionTerminatingCheck(i::Isolate* isolate) {
   if (isolate->has_scheduled_exception()) {
@@ -7907,6 +7917,10 @@ void Isolate::SetFatalErrorHandler(FatalErrorCallback that) {
   isolate->set_exception_behavior(that);
 }
 
+void Isolate::SetOOMErrorHandler(OOMErrorCallback that) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
+  isolate->set_oom_behavior(that);
+}
 
 void Isolate::SetAllowCodeGenerationFromStringsCallback(
     AllowCodeGenerationFromStringsCallback callback) {