Support explicit pools in actions

tools/gn/variables.cc

Index: tools/gn/variables.cc
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index bbb8791e1b4df358dd604e8506b86a82ba39b029..462fde312e7b00ebe38bf8ebfa8fdecd72a46992 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -929,24 +929,24 @@ Example
 
 const char kConsole[] = "console";

[brettw, 2017/06/28 21:23:27]

I think this can be deleted.

[Petr Hosek, 2017/06/28 23:42:32]

Done.

 const char kConsole_HelpShort[] =
-    "console: [boolean] Run this action in the console pool.";
+    "console: [label] Console pool object.";
 const char kConsole_Help[] =
-    R"(console: Run this action in the console pool.
+    R"(console: Console pool objects.
 
-  Boolean. Defaults to false.
-
-  Actions marked "console = true" will be run in the built-in ninja "console"
-  pool. They will have access to real stdin and stdout, and output will not be
-  buffered by ninja. This can be useful for long-running actions with progress
-  logs, or actions that require user input.
+  Console pool is a special pool object that uses the built-in ninja "console"
+  pool. Target using this pool will have access to real stdin and stdout, and
+  output will not be buffered by ninja. This can be useful for long-running
+  actions with progress logs, or actions that require user input.
 
   Only one console pool target can run at any one time in Ninja. Refer to the
   Ninja documentation on the console pool for more info.
 
 Example
 
-  action("long_action_with_progress_logs") {
-    console = true
+  action("my_action") {
+    ...
+    pool = console
+    ...
   }
 )";
 
@@ -1441,6 +1441,23 @@ const char kOutputs_Help[] =
     with no source expansions. See "gn help action".
 )";
 
+const char kPool[] = "pool";
+const char kPool_HelpShort[] =
+    "pool: [string] Label of the pool used by the action.";
+const char kPool_Help[] =
+    R"(pool: Label of the pool used by the action.
+
+  A fully-qualified label representing the pool that will be used for the
+  action. Pools are defined using the pool() {...} declaration.
+
+Example
+
+  action("action") {
+    pool = "//build:custom_pool"
+    ...
+  }
+)";
+
 const char kPrecompiledHeader[] = "precompiled_header";
 const char kPrecompiledHeader_HelpShort[] =
     "precompiled_header: [string] Header file to precompile.";
@@ -1921,6 +1938,7 @@ const VariableInfoMap& GetTargetVariables() {
     INSERT_VARIABLE(OutputName)
     INSERT_VARIABLE(OutputPrefixOverride)
     INSERT_VARIABLE(Outputs)
+    INSERT_VARIABLE(Pool)
     INSERT_VARIABLE(PrecompiledHeader)
     INSERT_VARIABLE(PrecompiledHeaderType)
     INSERT_VARIABLE(PrecompiledSource)