Module API (#32). r=waylonis, bryner

- Introduces a standard API for dealing with modules.  MinidumpModule
   is now a concrete implementation of this API.  Code may interact with
   single modules using the CodeModule interface, and collections of
   modules using its container, the CodeModules interface.
 - CodeModule is used directly by SymbolSupplier implementations and
   SourceLineResolver.  Reliance on the specific implementation in
   MinidumpModule has been eliminated.
 - Module lists are now added to ProcessState objects.  Module references
   in each stack frame are now pointers to objects in these module lists.
 - The sample minidump_stackwalk tool prints the module list after printing
   all threads' stacks.

http://groups.google.com/group/airbag-dev/browse_frm/thread/a9c0550edde54cf8


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@74 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/minidump_processor.cc

@@ -75,6 +75,14 @@ ProcessState* MinidumpProcessor::Process(const string &minidump_file) {
         &dump, &process_state->crash_address_);
   }
 
+  MinidumpModuleList *module_list = dump.GetModuleList();
+
+  // Put a copy of the module list into ProcessState object.  This is not
+  // necessarily a MinidumpModuleList, but it adheres to the CodeModules
+  // interface, which is all that ProcessState needs to expose.
+  if (module_list)
+    process_state->modules_ = module_list->Copy();
+
   MinidumpThreadList *threads = dump.GetThreadList();
   if (!threads) {
     return NULL;
@@ -137,10 +145,18 @@ ProcessState* MinidumpProcessor::Process(const string &minidump_file) {
       return NULL;
     }
 
+    // Use process_state->modules_ instead of module_list, because the
+    // |modules| argument will be used to populate the |module| fields in
+    // the returned StackFrame objects, which will be placed into the
+    // returned ProcessState object.  module_list's lifetime is only as
+    // long as the Minidump object: it will be deleted when this function
+    // returns.  process_state->modules_ is owned by the ProcessState object
+    // (just like the StackFrame objects), and is much more suitable for this
+    // task.
     scoped_ptr<Stackwalker> stackwalker(
         Stackwalker::StackwalkerForCPU(context,
                                        thread_memory,
-                                       dump.GetModuleList(),
+                                       process_state->modules_,
                                        supplier_));
     if (!stackwalker.get()) {
       return NULL;