Revert of Default components to static libraries in GN build

build/config/BUILDCONFIG.gn

Index: build/config/BUILDCONFIG.gn
diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index 1445e4af2ab4c09c512919242c1793dbf9562fd1..a55a56582fb4912befa3719d03e1fc7a9fb1c489 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -111,20 +111,11 @@
 #   even if the value is overridden, which is wasteful. See first bullet.
 
 declare_args() {
-  # Component build. Setting to true compiles targets declared as "components"
-  # as shared libraries loaded dynamically. This speeds up development time.
-  # When false, components will be linked statically.
+  # Component build.
   is_component_build = false
 
-  # Set to enable the official build level of optimization. This has nothing
-  # to do with branding, but enables an additional level of optimization above
-  # release (!is_debug). This might be better expressed as a tri-state
-  # (debug, release, official) but for historical reasons there are two
-  # separate flags.
-  is_official_build = false
-
-  # Debug build. Enabling official builds automatically sets is_debug to false.
-  is_debug = !is_official_build
+  # Debug build.
+  is_debug = true
 
   # Whether we're a traditional desktop unix.
   is_desktop_linux = current_os == "linux"
@@ -144,8 +135,6 @@
 
   # DON'T ADD MORE FLAGS HERE. Read the comment above.
 }
-
-assert(!(is_debug && is_official_build), "Can't do official debug builds")
 
 # ==============================================================================
 # TOOLCHAIN SETUP
@@ -607,38 +596,23 @@
 # ==============================================================================
 
 # Defines a component, which equates to a shared_library when
-# is_component_build == true and a static_library otherwise.
-#
-# Use static libraries for the static build rather than source sets because
-# many of of our test binaries link many large dependencies but often don't
-# use large portions of them. The static libraries are much more efficient to
-# link in this situation since only the necessary object files are linked.
-#
-# The invoker can override the type of the target in the non-component-build
-# case by setting static_component_type to either "source_set" or
-# "static_library". If unset, the default will be used.
+# is_component_build == true and a source_set / static_library otherwise.
+#
+# Arguments are the same as a normal library with this addition:
+#   component_never_use_source_set: Whether to use static_library instead of
+#       source_set for non-component builds. Some targets (e.g. //base) should
+#       use static_library rather than source_set to avoid linking unused object
+#       files.
 template("component") {
+  _never_use_source_set = defined(invoker.component_never_use_source_set) &&
+                          invoker.component_never_use_source_set
+  assert(_never_use_source_set || true)  # Mark as used.
   if (is_component_build) {
     _component_mode = "shared_library"
-  } else if (defined(invoker.static_component_type)) {
-    assert(invoker.static_component_type == "static_library" ||
-           invoker.static_component_type == "source_set")
-    _component_mode = invoker.static_component_type
-  } else if (!defined(invoker.sources) || is_mac ||
-             (is_win && is_official_build)) {
-    # When there are no sources defined, use a source set to avoid creating
-    # an empty static library (which generally don't work).
-    #
-    # On Windows official builds, the link time code generation bloats static
-    # libraries to the point where some of them become >32 bits large which
-    # causes lib.exe to fail. Always use source sets for that configuration.
-    #
-    # TODO(brettw) bug 618797: Remove the mac condition. On Mac making these as
-    # static_library causes crashes. Remove the mac condition above when this
-    # is fixed.
+  } else if (_never_use_source_set) {
+    _component_mode = "static_library"
+  } else {
     _component_mode = "source_set"
-  } else {
-    _component_mode = "static_library"
   }
   target(_component_mode, target_name) {
     # Explicitly forward visibility, implicitly forward everything else.