DevTools: Support async call stacks for FileSystem API (part 1).

Source/core/inspector/CodeGeneratorInstrumentation.py

Index: Source/core/inspector/CodeGeneratorInstrumentation.py
diff --git a/Source/core/inspector/CodeGeneratorInstrumentation.py b/Source/core/inspector/CodeGeneratorInstrumentation.py
index c31371766163373f9e931040a4b25fb3a24b68cd..7be51dbfa81dda485dab5aa1c982377757c8e30b 100755
--- a/Source/core/inspector/CodeGeneratorInstrumentation.py
+++ b/Source/core/inspector/CodeGeneratorInstrumentation.py
@@ -41,6 +41,8 @@ ${includes}
 
 namespace WebCore {
 
+${forward_declarations}
+
 namespace InspectorInstrumentation {
 
 $methods
@@ -195,6 +197,7 @@ class File:
         self.name = name
         self.header_name = self.name + "Inl"
         self.includes = [include_inspector_header("InspectorInstrumentation")]
+        self.forward_declarations = []
         self.declarations = []
         for line in map(str.strip, source.split("\n")):
             line = re.sub("\s{2,}", " ", line).strip()  # Collapse whitespace
@@ -202,9 +205,12 @@ class File:
                 continue
             if line[0] == "#":
                 self.includes.append(line)
+            elif line.startswith("class "):
+                self.forward_declarations.append(line)
             else:
                 self.declarations.append(Method(line))
         self.includes.sort()
+        self.forward_declarations.sort()
 
     def generate(self, cpp_lines, used_agents):
         header_lines = []
@@ -217,6 +223,7 @@ class File:
         return template_h.substitute(None,
                                      file_name=self.header_name,
                                      includes="\n".join(self.includes),
+                                     forward_declarations="\n".join(self.forward_declarations),
                                      methods="\n".join(header_lines))