Backport some work from sample to embedder:

runtime/embedders/android/vm_glue.cc

 // Copyright (c) 2012, 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 <math.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/stat.h>
 
 #include "include/dart_api.h"
@@ skipping 18 matching lines @@
   LOGE(format, arguments);
   va_end(arguments);
   Dart_ExitScope();
   Dart_ShutdownIsolate();
   LOGE("Shutdown isolate");
   return -1;
 }
 
 Dart_Handle VMGlue::CheckError(Dart_Handle handle) {
   if (Dart_IsError(handle)) {
-    LOGE("Unexpected Error Handle");
+    LOGE("Unexpected Error Handle: %s", Dart_GetError(handle));
     Dart_PropagateError(handle);
   }
   return handle;
 }
 
 #define CHECK_RESULT(result)                   \
   if (Dart_IsError(result)) {                  \
     *error = strdup(Dart_GetError(result));    \
     LOGE(*error);                              \
     Dart_ExitScope();                          \
     Dart_ShutdownIsolate();                    \
     return false;                              \
   }
 
 Dart_Handle VMGlue::LibraryTagHandler(Dart_LibraryTag tag,
                                       Dart_Handle library,
                                       Dart_Handle urlHandle) {
   const char* url;
   Dart_StringToCString(urlHandle, &url);
   if (tag == kCanonicalizeUrl) {
     return urlHandle;
   }
   // TODO(vsm): Split this up into separate libraries for 3D, 2D,
   // Touch, Audio, etc.  All builtin libraries should be handled here
   // (or moved into a snapshot).
   if (strcmp(url, "android_extension.dart") == 0) {
-    Dart_Handle source =
-        VMGlue::LoadSourceFromFile("/data/data/com.google.dartndk/app_dart/android_extension.dart");
+    Dart_Handle source = VMGlue::LoadSourceFromFile(
+        "/data/data/com.google.dartndk/app_dart/android_extension.dart");
     Dart_Handle library = CheckError(Dart_LoadLibrary(urlHandle, source));
     CheckError(Dart_SetNativeResolver(library, ResolveName));
     return library;
   }
   LOGE("UNIMPLEMENTED: load library %s\n", url);
   return NULL;
 }
 
 // Returns true on success, false on failure.
 bool VMGlue::CreateIsolateAndSetupHelper(const char* script_uri,
@@ skipping 26 matching lines @@
   return CreateIsolateAndSetupHelper(script_uri,
                                      main,
                                      data,
                                      error);
 }
 
 #define VMHOSTNAME  "android_dart_host"
 #define MAINSCRIPT  "/data/data/com.google.dartndk/app_dart/main.dart"
 
 const char* VM_FLAGS[] = {
-  "--enable_type_checks",
+  "--enable_type_checks",  // TODO(gram): This should be an option!
   "--trace_isolates",
   "--trace_natives",
 };
 
 int VMGlue::InitializeVM() {
   // We need the next call to get Dart_Initialize not to bail early.
   LOGI("Setting VM Options");
   Dart_SetVMFlags(sizeof(VM_FLAGS) / sizeof(VM_FLAGS[0]), VM_FLAGS);
 
   // Initialize the Dart VM, providing the callbacks to use for
@@ skipping 20 matching lines @@
     LOGE("Main script not found at: %s\n", url);
     return NULL;
   }
 
   struct stat sb;
   int fd = fileno(file);
   fstat(fd, &sb);
   int length = sb.st_size;
   LOGI("Entry file %s is %d bytes.\n", url, length);
 
-  char* buffer = reinterpret_cast<char *>(malloc((length + 1) * sizeof(char)));
+  char* buffer = new char[length+1];
   if (read(fd, buffer, length) < 0) {
     LOGE("Could not read script %s.\n", url);
     return NULL;
   }
   buffer[length] = 0;
   fclose(file);
 
   Dart_Handle contents = CheckError(Dart_NewStringFromCString(buffer));
-  free(buffer);
+  delete[] buffer;
   return contents;
 }
 
 int VMGlue::StartMainIsolate() {
   if (!initialized_vm_) {
     int rtn = InitializeVM();
     if (rtn != 0) return rtn;
   }
 
   // Create an isolate and loads up the application script.
@@ skipping 12 matching lines @@
   CheckError(Dart_LoadScript(url, source));
 
   Dart_ExitScope();
   Dart_ExitIsolate();
   return 0;
 }
 
 int VMGlue::CallSetup() {
   if (!initialized_script_) {
     initialized_script_ = true;
-    LOGI("Invoking setup");
+    LOGI("Invoking setup(0,0,%d,%d)", graphics_->width(), graphics_->height());
     Dart_EnterIsolate(isolate_);
     Dart_EnterScope();
-    Dart_Handle args[2];
-    args[0] = CheckError(Dart_NewInteger(graphics_->width()));
-    args[1] = CheckError(Dart_NewInteger(graphics_->height()));
-    int rtn = Invoke("setup", 2, args);
+    // We pass in x, y, w, h. x and y are always zero but we include them
+    // because for the same app running in web page with HTML canvas this
+    // will not be true.

[vsm, 2013/01/09 21:17:21]

Don't follow.  Why would x and y be non-zero for HTML?

[gram, 2013/01/09 22:33:28]

You're right. My browser based bubble app used the canvas coords on the page
here to normalize the mouse event coords to be canvas-relative, but that should
be handled beforehand so that any events to our Dart callbacks are already
canvas relative. Reverting.

+    Dart_Handle args[4];
+    args[0] = CheckError(Dart_NewInteger(0));
+    args[1] = CheckError(Dart_NewInteger(0));
+    args[2] = CheckError(Dart_NewInteger(graphics_->width()));
+    args[3] = CheckError(Dart_NewInteger(graphics_->height()));
+    int rtn = Invoke("setup", 4, args);
     Dart_ExitScope();
     Dart_ExitIsolate();
     LOGI("Done setup");
     return rtn;
   }
   return 0;
 }
 
 int VMGlue::CallUpdate() {
   if (initialized_script_) {
@@ skipping 12 matching lines @@
 int VMGlue::OnMotionEvent(const char* pFunction, int64_t pWhen,
   float pMoveX, float pMoveY) {
   if (initialized_script_) {
     LOGI("Invoking %s", pFunction);
     Dart_EnterIsolate(isolate_);
     Dart_EnterScope();
     Dart_Handle args[3];
     args[0] = CheckError(Dart_NewInteger(pWhen));
     args[1] = CheckError(Dart_NewDouble(pMoveX));
     args[2] = CheckError(Dart_NewDouble(pMoveY));
-    int rtn = Invoke(pFunction, 3, args);
+    int rtn = Invoke(pFunction, 3, args, false);
     Dart_ExitScope();
     Dart_ExitIsolate();
     LOGI("Done %s", pFunction);
     return rtn;
   }
   return -1;
 }
 
 int VMGlue::OnKeyEvent(const char* function, int64_t when, int32_t flags,
        int32_t key_code, int32_t meta_state, int32_t repeat) {
   if (initialized_script_) {
     LOGI("Invoking %s", function);
     Dart_EnterIsolate(isolate_);
     Dart_EnterScope();
     Dart_Handle args[5];
     args[0] = CheckError(Dart_NewInteger(when));
     args[1] = CheckError(Dart_NewInteger(flags));
     args[2] = CheckError(Dart_NewInteger(key_code));
     args[3] = CheckError(Dart_NewInteger(meta_state));
     args[4] = CheckError(Dart_NewInteger(repeat));
-    int rtn = Invoke(function, 5, args);
+    int rtn = Invoke(function, 5, args, false);
     Dart_ExitScope();
     Dart_ExitIsolate();
     LOGI("Done %s", function);
     return rtn;
   }
   return -1;
 }
 
-int VMGlue::Invoke(const char* function, int argc, Dart_Handle* args) {
-  Dart_Handle result;
-
+int VMGlue::Invoke(const char* function,
+                   int argc,
+                   Dart_Handle* args,
+                   bool failIfNotDefined) {
   LOGI("in invoke(%s)", function);
 
   // Lookup the library of the root script.
   LOGI("looking up the root library");
   Dart_Handle library = Dart_RootLibrary();
   if (Dart_IsNull(library)) {
      return ErrorExit("Unable to find root library\n");
   }
 
+  Dart_Handle nameHandle = Dart_NewStringFromCString(function);
+
+  if (!failIfNotDefined) {
+    // TODO(gram) - this doesn't work - we need a way of seeing if
+    // the function is defined before we call it.
+    // Dart_Handle h = Dart_LookupVariable(library, nameHandle);
+    // if (Dart_IsNull(h)) {

[vsm, 2013/01/09 21:17:21]

I think you want Dart_LookupFunction instead here.  Although, I'd be fine with
removing this in favor of the "Temp hack" below - doesn't seem so bad to me.  Up
to you.

[gram, 2013/01/09 22:33:28]

I tried a few different things here, so I may have tried Dart_LookupFunction
already. IIRC there was one that worked for class methods but not top-level
functions, or something like that. For now I'll just go with the 'temp hack'.

+      // LOGE("%s is not defined", function);
+      // LOGI("out invoke");
+      // return 0;
+    // }
+  }
   // Lookup and invoke the appropriate function.
   LOGI("invoking %s", function);
-  result =
-      Dart_Invoke(library, Dart_NewStringFromCString(function), argc, args);
+  Dart_Handle result = Dart_Invoke(library, nameHandle, argc, args);
 
   if (Dart_IsError(result)) {
-    return ErrorExit("%s\n", Dart_GetError(result));
+    if (failIfNotDefined) {  // Temp hack; see above.
+      return ErrorExit("Invoke %s: %s\n", function, Dart_GetError(result));
+    } else {
+      LOGE("Invoke %s: %s", function, Dart_GetError(result));
+    }
   }
 
   // TODO(vsm): I don't think we need this.
   // Keep handling messages until the last active receive port is closed.
   LOGI("Entering Dart message loop");
   result = Dart_RunLoop();
   if (Dart_IsError(result)) {
-    return ErrorExit("%s\n", Dart_GetError(result));
+    return ErrorExit("Dart_RunLoop: %s\n", Dart_GetError(result));
   }
 
   LOGI("out invoke");
   return 0;
 }
 
 void VMGlue::FinishMainIsolate() {
   LOGI("Finish main isolate");
   Dart_EnterIsolate(isolate_);
   // Shutdown the isolate.
   Dart_ShutdownIsolate();
   isolate_ = NULL;
   initialized_script_ = false;
 }