Add support for component=shared_library for base_unittests_run.

base/base.isolate

+# Copyright (c) 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+{
+  'conditions': [
+    ['OS=="linux" and component=="shared_library"', {
+      'variables': {
+        'isolate_dependency_tracked': [
+          '<(PRODUCT_DIR)/lib/libbase.so',
+          '<(PRODUCT_DIR)/lib/libbase_i18n.so',
+          '<(PRODUCT_DIR)/lib/libbase_prefs.so',
+        ],
+      },
+    }],
+    ['OS=="mac" and component=="shared_library"', {
+      'variables': {
+        'isolate_dependency_tracked': [
+          '<(PRODUCT_DIR)/libbase.dylib',
+          '<(PRODUCT_DIR)/libbase_i18n.dylib',
+          '<(PRODUCT_DIR)/libbase_prefs.dylib',
+        ],
+      },
+    }],
+    ['OS=="win" and component=="shared_library"', {
+      'variables': {
+        'isolate_dependency_tracked': [
+          '<(PRODUCT_DIR)/base.dll',
+          '<(PRODUCT_DIR)/base_i18n.dll',
+          '<(PRODUCT_DIR)/base_prefs.dll',
+        ],
+      },
+    }],
+  ],
+  'includes': [
+    '../net/third_party/nss/ssl.isolate',

[Ryan Sleevi, 2014/01/21 19:43:50]

Why are you including this isolate unconditionally.

base.gyp depends on system.gyp:ssl, which handles use_openssl=1 and
use_openssl=0.

This will unconditionally include the NSS bits on OpenSSL, which doesn't seem
correct.

[M-A Ruel, 2014/01/21 19:54:45]

There's no way to include conditionally. It is true of GYP too btw.
The condition in ssl.isolate prevails.

[Ryan Sleevi, 2014/01/21 20:39:09]

Can we not preserve the same level of 'indirection' that base.gyp has - namely,
it #includes build/linux/system.isolate, which can then unconditionally include
net/third_party/nss/ssl.isolate or any other isolates?

The reason I ask is that this flattens a layer of the dependency, which makes it
harder to maintain, in terms of the .isolate files living next to their .gyp
files. I agree it creates more maintenance to have an extra .isolate file
around, but at least the chain of .isolates match their chain of .gyp, and as we
cleanup .gyp, we remember to clean up .isolate

[M-A Ruel, 2014/01/21 21:01:55]

I can't, the language is intentionally not expressive enough. You can't
reference a gyp target, the gyp->isolate jump is one-way. Even if there were a
build/linux/system.isolate, it would contain a single 'includes' in it, which
makes it less maintainable IMHO. The other way is to merge
net/third_party/nss/ssl.isolate right here, which I had initially done and is
even more flat but easy to understand.

+    '../third_party/icu/icu.isolate',
+  ],
+}