Support tagged module references

There are cases where a module needs to refer to an intermediate
output of another module instead of its final output.  For example,
a module may want to use the .jar containing .class files from
another module whose final output is a .jar containing classes.dex
files.  Support a new ":module{.tag}" format in any property that
is annotated with `android:"path"`, which will query the target
module for its ".tag" output(s).

Test: path_properties_test.go, paths_test.go
Test: no unexpected changes in build.ninja
Change-Id: Icd3c9b0d83ff125771767c04046fcffb9fc3f65a

android/module_test.go

@@ -0,0 +1,141 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import "testing"
+
+func TestSrcIsModule(t *testing.T) {
+	type args struct {
+		s string
+	}
+	tests := []struct {
+		name       string
+		args       args
+		wantModule string
+	}{
+		{
+			name: "file",
+			args: args{
+				s: "foo",
+			},
+			wantModule: "",
+		},
+		{
+			name: "module",
+			args: args{
+				s: ":foo",
+			},
+			wantModule: "foo",
+		},
+		{
+			name: "tag",
+			args: args{
+				s: ":foo{.bar}",
+			},
+			wantModule: "foo{.bar}",
+		},
+		{
+			name: "extra colon",
+			args: args{
+				s: ":foo:bar",
+			},
+			wantModule: "foo:bar",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if gotModule := SrcIsModule(tt.args.s); gotModule != tt.wantModule {
+				t.Errorf("SrcIsModule() = %v, want %v", gotModule, tt.wantModule)
+			}
+		})
+	}
+}
+
+func TestSrcIsModuleWithTag(t *testing.T) {
+	type args struct {
+		s string
+	}
+	tests := []struct {
+		name       string
+		args       args
+		wantModule string
+		wantTag    string
+	}{
+		{
+			name: "file",
+			args: args{
+				s: "foo",
+			},
+			wantModule: "",
+			wantTag:    "",
+		},
+		{
+			name: "module",
+			args: args{
+				s: ":foo",
+			},
+			wantModule: "foo",
+			wantTag:    "",
+		},
+		{
+			name: "tag",
+			args: args{
+				s: ":foo{.bar}",
+			},
+			wantModule: "foo",
+			wantTag:    ".bar",
+		},
+		{
+			name: "empty tag",
+			args: args{
+				s: ":foo{}",
+			},
+			wantModule: "foo",
+			wantTag:    "",
+		},
+		{
+			name: "extra colon",
+			args: args{
+				s: ":foo:bar",
+			},
+			wantModule: "foo:bar",
+		},
+		{
+			name: "invalid tag",
+			args: args{
+				s: ":foo{.bar",
+			},
+			wantModule: "foo{.bar",
+		},
+		{
+			name: "invalid tag 2",
+			args: args{
+				s: ":foo.bar}",
+			},
+			wantModule: "foo.bar}",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotModule, gotTag := SrcIsModuleWithTag(tt.args.s)
+			if gotModule != tt.wantModule {
+				t.Errorf("SrcIsModuleWithTag() gotModule = %v, want %v", gotModule, tt.wantModule)
+			}
+			if gotTag != tt.wantTag {
+				t.Errorf("SrcIsModuleWithTag() gotTag = %v, want %v", gotTag, tt.wantTag)
+			}
+		})
+	}
+}