Support explicit pools in actions

tools/gn/functions.cc

Index: tools/gn/functions.cc
diff --git a/tools/gn/functions.cc b/tools/gn/functions.cc
index 272cd9430bc96d82fef310a8f8ef5600cd3e2725..06d45d2498ca0b72c8d5b6296f05553b5a27ade8 100644
--- a/tools/gn/functions.cc
+++ b/tools/gn/functions.cc
@@ -733,11 +733,14 @@ const char kPool_Help[] =
   context of more than one toolchain it is recommended to specify an
   explicit toolchain when defining and referencing a pool.
 
+  A pool marked "console = true" will use the built-in ninja "console"
+  pool and cannot specify "depth" which is always 1.
+
   A pool is referenced by its label just like a target.
 
 Variables
 
-  depth*
+  console, depth*
   * = required
 
 Example
@@ -775,25 +778,41 @@ Value RunPool(const FunctionCallNode* function,
   if (g_scheduler->verbose_logging())
     g_scheduler->Log("Defining pool", label.GetUserVisibleName(true));
 
-  // Get the pool depth. It is an error to define a pool without a depth,
-  // so check first for the presence of the value.
-  const Value* depth = scope->GetValue(kDepth, true);
-  if (!depth) {
-    *err = Err(function, "Can't define a pool without depth.");
-    return Value();
+  // Create the new pool.
+  std::unique_ptr<Pool> pool(new Pool(scope->settings(), label));
+
+  // Check the value of console.
+  const Value* console = scope->GetValue(variables::kConsole, true);
+  if (console) {
+    if (!console->VerifyTypeIs(Value::BOOLEAN, err))
+      return Value();
   }
 
-  if (!depth->VerifyTypeIs(Value::INTEGER, err))
-    return Value();
+  // Get the pool depth. Pool must hae a depth or be a console pool.
+  const Value* depth = scope->GetValue(kDepth, true);
+  if (console && console->boolean_value()) {
+    if (depth) {
+      *err = Err(function, "Can't define a console pool with depth.");
+      return Value();
+    }
 
-  if (depth->int_value() < 0) {
-    *err = Err(function, "depth must be positive or nul.");
-    return Value();
-  }
+    pool->set_console(console->boolean_value());
+  } else {
+    if (!depth) {
+      *err = Err(function, "Can't define a pool without depth.");
+      return Value();
+    }
 
-  // Create the new pool.
-  std::unique_ptr<Pool> pool(new Pool(scope->settings(), label));
-  pool->set_depth(depth->int_value());
+    if (!depth->VerifyTypeIs(Value::INTEGER, err))
+      return Value();
+
+    if (depth->int_value() < 0) {
+      *err = Err(function, "depth must be positive or nul.");
+      return Value();
+    }
+
+    pool->set_depth(depth->int_value());
+  }
 
   // Save the generated item.
   Scope::ItemVector* collector = scope->GetItemCollector();