[api] Templatize do_callback parameter in CallDepthScope

Drive-by-fix: mark isolates as const in stack-allocated scopes

BUG=chromium:630217

Review-Url: https://codereview.chromium.org/2220993003
Cr-Commit-Position: refs/heads/master@{#38496}

include/v8.h

@@ -957,7 +957,7 @@ class V8_EXPORT SealHandleScope {
   void* operator new(size_t size);
   void operator delete(void*, size_t);
 
-  internal::Isolate* isolate_;
+  internal::Isolate* const isolate_;
   internal::Object** prev_limit_;
   int prev_sealed_level_;
 };
@@ -5694,7 +5694,7 @@ class V8_EXPORT Isolate {
     ~SuppressMicrotaskExecutionScope();
 
    private:
-    internal::Isolate* isolate_;
+    internal::Isolate* const isolate_;
 
     // Prevent copying of Scope objects.
     SuppressMicrotaskExecutionScope(const SuppressMicrotaskExecutionScope&);

src/api.cc

@@ -86,7 +86,7 @@ namespace v8 {
     return bailout_value;                                            \
   }                                                                  \
   HandleScopeClass handle_scope(isolate);                            \
-  CallDepthScope call_depth_scope(isolate, context, do_callback);    \
+  CallDepthScope<do_callback> call_depth_scope(isolate, context);    \
   LOG_API(isolate, class_name, function_name);                       \
   ENTER_V8(isolate);                                                 \
   bool has_pending_exception = false
@@ -170,15 +170,11 @@ void CheckMicrotasksScopesConsistency(i::Isolate* isolate) {
 }
 #endif
 
-
+template <bool do_callback>
 class CallDepthScope {
  public:
-  explicit CallDepthScope(i::Isolate* isolate, Local<Context> context,
-                          bool do_callback)
-      : isolate_(isolate),
-        context_(context),
-        escaped_(false),
-        do_callback_(do_callback) {
+  explicit CallDepthScope(i::Isolate* isolate, Local<Context> context)
+      : isolate_(isolate), context_(context), escaped_(false) {
     // TODO(dcarney): remove this when blink stops crashing.
     DCHECK(!isolate_->external_caught_exception());
     isolate_->IncrementJsCallsFromApiCounter();
@@ -194,14 +190,14 @@ class CallDepthScope {
         context_->Enter();
       }
     }
-    if (do_callback_) isolate_->FireBeforeCallEnteredCallback();
+    if (do_callback) isolate_->FireBeforeCallEnteredCallback();
   }
   ~CallDepthScope() {
     if (!context_.IsEmpty()) context_->Exit();
     if (!escaped_) isolate_->handle_scope_implementer()->DecrementCallDepth();
-    if (do_callback_) isolate_->FireCallCompletedCallback();
+    if (do_callback) isolate_->FireCallCompletedCallback();
 #ifdef DEBUG
-    if (do_callback_) CheckMicrotasksScopesConsistency(isolate_);
+    if (do_callback) CheckMicrotasksScopesConsistency(isolate_);
 #endif
   }
 
@@ -909,12 +905,9 @@ i::Object** EscapableHandleScope::Escape(i::Object** escape_value) {
   return escape_slot_;
 }
 
-
-SealHandleScope::SealHandleScope(Isolate* isolate) {
-  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
-
-  isolate_ = internal_isolate;
-  i::HandleScopeData* current = internal_isolate->handle_scope_data();
+SealHandleScope::SealHandleScope(Isolate* isolate)
+    : isolate_(reinterpret_cast<i::Isolate*>(isolate)) {
+  i::HandleScopeData* current = isolate_->handle_scope_data();
   prev_limit_ = current->limit;
   current->limit = current->next;
   prev_sealed_level_ = current->sealed_level;

src/isolate.h

@@ -1497,9 +1497,9 @@ class SaveContext BASE_EMBEDDED {
   Isolate* isolate() { return isolate_; }
 
  private:
-  Isolate* isolate_;
+  Isolate* const isolate_;
   Handle<Context> context_;
-  SaveContext* prev_;
+  SaveContext* const prev_;
   Address c_entry_fp_;
 };