ScriptPromiseResolver: In debug builds, gather the construction stack trace.

This should allow us to determine which resolvers are not being properly
resolved or detached.

Bug: 873980
Change-Id: I44ead90aaf8b963b7380ba70c56c73ae2b7ad7d1
Reviewed-on: https://chromium-review.googlesource.com/c/1344822Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610936}

third_party/blink/renderer/bindings/core/v8/script_promise_resolver.cc

@@ -8,6 +8,10 @@
 #include "third_party/blink/renderer/core/execution_context/execution_context.h"
 #include "third_party/blink/renderer/core/probe/core_probes.h"
 
+#if DCHECK_IS_ON()
+#include "base/debug/alias.h"
+#endif
+
 namespace blink {
 
 ScriptPromiseResolver::ScriptPromiseResolver(ScriptState* script_state)
@@ -21,6 +25,25 @@ ScriptPromiseResolver::ScriptPromiseResolver(ScriptState* script_state)
   }
 }
 
+#if DCHECK_IS_ON()
+ScriptPromiseResolver::~ScriptPromiseResolver() {
+  // This is here temporarily to make it easier to track down which promise
+  // resolvers are being abandoned.
+  // TODO(crbug.com/873980): Remove this.
+  base::debug::StackTrace create_stack_trace(create_stack_trace_);
+  base::debug::Alias(&create_stack_trace);
+
+  // This assertion fails if:
+  //  - promise() is called at least once and
+  //  - this resolver is destructed before it is resolved, rejected,
+  //    detached, the V8 isolate is terminated or the associated
+  //    ExecutionContext is stopped.
+  DCHECK(state_ == kDetached || !is_promise_called_ ||
+         !GetScriptState()->ContextIsValid() || !GetExecutionContext() ||
+         GetExecutionContext()->IsContextDestroyed());
+}
+#endif
+
 void ScriptPromiseResolver::Reject(ExceptionState& exception_state) {
   DCHECK(exception_state.HadException());
   Reject(exception_state.GetException());

third_party/blink/renderer/bindings/core/v8/script_promise_resolver.h

@@ -18,6 +18,10 @@
 #include "third_party/blink/renderer/platform/web_task_runner.h"
 #include "v8/include/v8.h"
 
+#if DCHECK_IS_ON()
+#include "base/debug/stack_trace.h"
+#endif
+
 namespace blink {
 
 // This class wraps v8::Promise::Resolver and provides the following
@@ -49,16 +53,7 @@ class CORE_EXPORT ScriptPromiseResolver
   // from the destructor's assert.
   EAGERLY_FINALIZE();
 
-  ~ScriptPromiseResolver() override {
-    // This assertion fails if:
-    //  - promise() is called at least once and
-    //  - this resolver is destructed before it is resolved, rejected,
-    //    detached, the V8 isolate is terminated or the associated
-    //    ExecutionContext is stopped.
-    DCHECK(state_ == kDetached || !is_promise_called_ ||
-           !GetScriptState()->ContextIsValid() || !GetExecutionContext() ||
-           GetExecutionContext()->IsContextDestroyed());
-  }
+  ~ScriptPromiseResolver() override;
 #endif
 
   // Anything that can be passed to toV8 can be passed to this function.
@@ -179,6 +174,8 @@ class CORE_EXPORT ScriptPromiseResolver
 #if DCHECK_IS_ON()
   // True if promise() is called.
   bool is_promise_called_ = false;
+
+  base::debug::StackTrace create_stack_trace_{8};
 #endif
 };