[observatory] Add a 'GC' button to heap map.

runtime/vm/service.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 3459 matching lines @@
 #endif  // defined(DEBUG)
 
 
 static const MethodParameter* get_heap_map_params[] = {
     RUNNABLE_ISOLATE_PARAMETER, NULL,
 };
 
 
 static bool GetHeapMap(Thread* thread, JSONStream* js) {
   Isolate* isolate = thread->isolate();
+  bool should_collect = false;
+  if (js->HasParam("gc")) {
+    if (js->ParamIs("gc", "full")) {
+      should_collect = true;
+    } else {
+      PrintInvalidParamError(js, "gc");
+      return true;
+    }
+  }
+  if (should_collect) {
+    isolate->heap()->CollectAllGarbage();
+  }
   isolate->heap()->PrintHeapMapToJSONStream(isolate, js);
   return true;
 }
 
 
 static const char* snapshot_roots_names[] = {
     "User", "VM", NULL,
 };
 
 
@@ skipping 841 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart