Extract the shell runner into devtools.

README.md

 Mojo
 ====
 
 Mojo is an effort to extract a common platform out of Chrome's renderer and
 plugin processes that can support multiple types of sandboxed content, such as
 HTML, Pepper, or NaCl.
 
 ## Set-up and code check-out
 
 The instructions below only need to be done once. Note that a simple "git clone"
@@ skipping 194 matching lines @@
 Because the dart analyzer is a bit slow, we don't run it unless the user
 specifically asks for it. To run the dart analyzer against the list of dart
 targets in the toplevel BUILD.gn file, run:
 
 ```
 $ mojo/tools/mojob.py dartcheck
 ```
 
 ## Run Mojo Shell
 
-`mojo_shell.py` is a universal shell runner abstracting away the differences
-between running on Linux and Android. Having built Mojo as described above, a
-demo app can be run as follows:
+Devtools script `mojo_shell` is a universal shell runner abstracting away the
+differences between running on Linux and Android. Having built Mojo as
+described above, a demo app can be run as follows:
 
 ```
-mojo/tools/mojo_shell.py mojo:spinning_cube  # Linux.
-mojo/tools/mojo_shell.py mojo:spinning_cube  --android # Android.
+mojo/devtools/common/mojo_shell mojo:spinning_cube  # Linux.
+mojo/devtools/common/mojo_shell mojo:spinning_cube  --android # Android.
 ```
 
 Pass `--sky path_to_sky_file` to run a
 [Sky](https://github.com/domokit/mojo/tree/master/sky) app on either platform:
 ```
-mojo/tools/mojo_shell.py --sky sky/examples/raw/hello_world.dart
-mojo/tools/mojo_shell.py --sky sky/examples/raw/hello_world.dart --android
+mojo/devtools/common/mojo_shell --sky sky/examples/raw/hello_world.dart
+mojo/devtools/common/mojo_shell --sky sky/examples/raw/hello_world.dart --android
 ```
 
 Passing the `-v` flag will increase the output verbosity. In particular, it will
 also print all arguments passed by `mojo_shell.py` to the shell binary.
 
 ### Chromoting
 
 Some Mojo apps (Sky apps in particular) will need the --use-osmesa flag to run
 over [chromoting](https://support.google.com/chrome/answer/1649523?hl=en):
 
 ```
 mojo/tools/mojo_shell.py --sky sky/examples/raw/hello_world.dart --use-osmesa
 ```
 
 ### <a name="debugging"></a>Debugging, tracing, profiling
 
 #### Tracing
 While the shell is running, the `debugger` script allows you to interactively
 start
 [tracing](https://www.chromium.org/developers/how-tos/trace-event-profiling-tool)
 and retrieve the result:
 
 ```
-devtools/common/debugger tracing start
-devtools/common/debugger tracing stop [result.json]
+mojo/devtools/common/debugger tracing start
+mojo/devtools/common/debugger tracing stop [result.json]
 ```
 
 The trace file can be then loaded using the trace viewer in Chrome available at
 `about://tracing`.
 
 #### Android crash stacks
 When Mojo shell crashes on Android ("Unfortunately, Mojo shell has stopped.")
 due to a crash in native code, `debugger` can be used to find and symbolize the
 stack trace present in the device log:
 
@@ skipping 28 matching lines @@
 
 #### Device
 
 **The device has to be running Android 5.0 (Lollipop) or newer.**
 
 Many features useful for development (ie. streaming of the shell stdout when
 running shell on the device) will not work unless the device is rooted and
 running a userdebug build. For Googlers, [follow the instructions at this
 link](http://go/mojo-internal-build-instructions).
 
-#### Aw, snap!
-
-If the shell crashes on the device, you won't see symbols. Use
-`tools/android_stack_parser/stack` to map back to symbols, e.g.:
-```
-adb logcat | ./tools/android_stack_parser/stack
-```
-
 ### Running manually on Linux
 
 If you wish to, you can also run the Linux Mojo shell directly with no wrappers:
 ```
 ./out/Debug/mojo_shell mojo:spinning_cube
 ```