Closure: update doc to advocate for v2 and deprecate v1

docs/closure_compilation.md

 # Closure Compilation
 
 ## I just need to fix the compile!
 
-To locally run closure compiler like the bots, do this:
+### Pre-requisites
 
+You'll need Java 7 (preferably the OpenJDK version).  To install on Ubuntu:
 ```shell
-cd $CHROMIUM_SRC
-# sudo apt-get install openjdk-7-jre # may be required
-GYP_GENERATORS=ninja tools/gyp/gyp --depth . third_party/closure_compiler/compiled_resources.gyp
+sudo apt-get install openjdk-7-jre
+```
+
+On Mac or Windows, visit:
+[http://www.oracle.com/technetwork/java/javase/downloads/index.html](http://www.oracle.com/technetwork/java/javase/downloads/index.html)
+
+### Using ninja to compile the code
+
+We use GYP and ninja as our build system. To generate the ninja files from GYP:
+```shell
+# notice the 2 in compiled_resources.gyp
+GYP_GENERATORS=ninja tools/gyp/gyp --depth . third_party/closure_compiler/compiled_resources2.gyp
+```
+
+To compile the JavaScript:
+```shell
 ninja -C out/Default
 ```
 
-To run the v2 gyp format, change the last 2 lines to:
+The output should look something like this:
+```shell
+ninja: Entering directory `out/Default/'
+[30/106] ACTION Compiling chrome/browser/resources/md_history/constants.js
+```
 
+To generate and run the **deprecated** v1 gyp format, remove the "2" from "compiled_resources2.gyp":
 ```shell
-# notice the 2 in compiled_resources2.gyp
-GYP_GENERATORS=ninja tools/gyp/gyp --depth . third_party/closure_compiler/compiled_resources2.gyp
+$ GYP_GENERATORS=ninja tools/gyp/gyp --depth . third_party/closure_compiler/compiled_resources.gyp
+```
+
+Compiling works the same way for both v1 and v2 systems:
+```shell
 ninja -C out/Default

[dpapad, 2016/03/09 20:19:22]

Nit(optional): You might want to add a note of *never* trying this with
-jBIG_NUMBER_HERE, because it is all local, and will freeze your machine. (I had
to shutdown and restart to recover my machine a while ago when I did this
mistake).

[Dan Beam, 2016/03/09 21:53:55]

Done.

 ```
 
 ## Background
 
 In C++ and Java, compiling the code gives you _some_ level of protection against
 misusing variables based on their type information. JavaScript is loosely typed
 and therefore doesn't offer this safety. This makes writing JavaScript more
 error prone as it's _one more thing_ to mess up.
 
 Because having this safety is handy, Chrome now has a way to optionally
@@ skipping 249 matching lines @@
           'jscomp_error=duplicate',
           'jscomp_error=misplacedTypeAnnotation',
         ],
         'disabled_closure_args': [], # remove the disabled closure args for more strict compilation
       },
       'includes': ['../third_party/closure_compiler/compile_js.gypi'],
     },
   ],
 }
 ```