Merge pull request #1666 from abarth/null_dx
The dx and dy properties of PointerInputEvents shouldn't be null
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 672a1a0..d2c2c50 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -6,8 +6,14 @@
Things you will need
--------------------
- * git
- * an IDE. We recommend [Atom](https://github.com/flutter/engine/wiki/Using-Atom-with-Flutter).
+ * git (used for source version control).
+ * An IDE. We recommend [Atom](https://github.com/flutter/engine/wiki/Using-Atom-with-Flutter).
+ * An ssh client (used to authenticate with GitHub).
+ * Chromium's [depot_tools](http://www.chromium.org/developers/how-tos/install-depot-tools) (make sure it's in your path). We use the 'gclient' tool from depot_tools.
+ * Python (used by many of our tools, including 'gclient').
+ * curl (used by `gclient sync`).
+
+You do not need [Dart](https://www.dartlang.org/downloads/linux.html) installed, as a Dart tool chain is automatically downloaded as part of the "getting the code" step.
Getting the code
----------------
@@ -15,8 +21,6 @@
To get the code:
* Fork `https://github.com/flutter/engine` into your own GitHub account.
- * [Download and install](http://www.chromium.org/developers/how-tos/install-depot-tools) Chromium's [depot_tools](http://www.chromium.org/developers/how-tos/install-depot-tools)
- and make sure it is in your path. We use the 'gclient' tool from depot_tools.
* If you haven't configured your machine with an SSH key that's shared by github then
follow the directions here: https://help.github.com/articles/generating-ssh-keys/.
* Create an empty directory for your copy of the repository. Call it what you like. For
@@ -37,10 +41,11 @@
]
target_os = ["android"]
```
- * `cd flutter`
- * `gclient sync`
- * `cd src`
- * `git remote add upstream git@github.com:flutter/engine.git`
+ * `cd flutter` (Change to the directory in which you put the `.gclient` file)
+ * `gclient sync` This will fetch all the source code that Flutter depends on. Avoid interrupting this script, it can leave your repository in an inconsistent state that is tedious to clean up.
+ * `cd src` (Change to the directory that `gclient sync` created in your `flutter` directory)
+ * `git remote add upstream git@github.com:flutter/engine.git` (So that you fetch from the master repository, not your clone, when running `git fetch` et al)
+ * Add `.../flutter/src/third_party/dart-sdk/dart-sdk/bin/` to your path so that you can run the `pub` tool more easily.
Building the code
-----------------
