Gut gyp_chromium, common.gypi.

docs/ccache_mac.md

 # Using CCache on Mac
 
 [ccache](http://ccache.samba.org/) is a compiler cache. It speeds up
 recompilation of C/C++ code by caching previous compilations and detecting when
 the same compilation is being done again. This often results in a significant
 speedup in common compilations, especially when switching between branches. This
 page is about using ccache on Mac with clang and the NinjaBuild system.
 
 [TOC]
 
@@ skipping 21 matching lines @@
 ./autogen.sh
 ./configure && make && make install
 ```
 
 Make sure ccache can be found in your `$PATH`.
 
 You can also just use the current released version of ccache (3.1.8 or 3.1.9)
 and disable the chromium style plugin with `clang_use_chrome_plugins=0` in your
 `GYP_DEFINES`.
 
-## Use with GYP
-
-We have to set two environment variables (`CC` and `CXX`) before calling
-`gclient runhooks` or `build/gyp_chromium`, given you are currently in the
-`chromium/src` directory:
-
-```shell
-export CC="ccache clang -Qunused-arguments"
-export CXX="ccache clang++ -Qunused-arguments"
-```
-
-Then run:
-
-```shell
-GYP_GENERATORS="ninja" ./build/gyp_chromium
-```
-
-or
-
-```shell
-GYP_GENERATORS="ninja" gclient runhooks
-```
-
-(Instead of relying on the clang/clang++ for building chromium in your `$PATH`,
-you can also use the absolute path here.)
-
 ## Use with GN
 
 You just need to set the use\_ccache variable. Do so like the following:
 
 ```shell
 gn gen out-gn --args='cc_wrapper="ccache"'
 ```
 
 ## Build
 
@@ skipping 12 matching lines @@
 ninja -C out/Release chrome
 ```
 
 ## Optional Steps
 
 *   Configure ccache to use a different cache size with `ccache -M <max size>`.
     You can see a list of configuration options by calling ccache alone.  * The
     default ccache directory is `~/.ccache`. You might want to symlink it to
     another directory (for example, when using FileVault for your home
     directory).