Add build progress in Soong UI

Soong UI generates a proto file named build_progress.pb in $(OUT_DIR)
output directory that contains build action numbers (how many are executing,
finished and total) during the course of a build. This is for external
systems that invokes the Platform Build Systems and would like to know
the completion status.

Bug: b/150401146
Test: Wrote a bash script that continuously read the
build_progress.pb file and computed the build completed percentage
while building the aosp_arm-eng target. Compared the percentage between
the Soong output console and the one reported by the bash script.

Change-Id: I7c7347bc8e41958093892d8e2731c4f4169937dd

ui/status/build_progress_proto/build_progress.pb.go

@@ -0,0 +1,115 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: build_progress.proto
+
+package soong_build_progress_proto
+
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type BuildProgress struct {
+	// Total number of actions in a build. The total actions will increase
+	// and might decrease during the course of a build.
+	TotalActions *uint64 `protobuf:"varint,1,opt,name=total_actions,json=totalActions" json:"total_actions,omitempty"`
+	// Total number of completed build actions. This value will never decrease
+	// and finished_actions <= total_actions. At one point of the build, the
+	// finished_actions will be equal to total_actions. This may not represent
+	// that the build is completed as the total_actions may be increased for
+	// additional counted work or is doing non-counted work.
+	FinishedActions *uint64 `protobuf:"varint,2,opt,name=finished_actions,json=finishedActions" json:"finished_actions,omitempty"`
+	// Total number of current actions being executed during a course of a
+	// build and current_actions + finished_actions <= total_actions.
+	CurrentActions *uint64 `protobuf:"varint,3,opt,name=current_actions,json=currentActions" json:"current_actions,omitempty"`
+	// Total number of actions that reported as a failure.
+	FailedActions        *uint64  `protobuf:"varint,4,opt,name=failed_actions,json=failedActions" json:"failed_actions,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *BuildProgress) Reset()         { *m = BuildProgress{} }
+func (m *BuildProgress) String() string { return proto.CompactTextString(m) }
+func (*BuildProgress) ProtoMessage()    {}
+func (*BuildProgress) Descriptor() ([]byte, []int) {
+	return fileDescriptor_a8a463f8e30dab2e, []int{0}
+}
+
+func (m *BuildProgress) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_BuildProgress.Unmarshal(m, b)
+}
+func (m *BuildProgress) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_BuildProgress.Marshal(b, m, deterministic)
+}
+func (m *BuildProgress) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_BuildProgress.Merge(m, src)
+}
+func (m *BuildProgress) XXX_Size() int {
+	return xxx_messageInfo_BuildProgress.Size(m)
+}
+func (m *BuildProgress) XXX_DiscardUnknown() {
+	xxx_messageInfo_BuildProgress.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_BuildProgress proto.InternalMessageInfo
+
+func (m *BuildProgress) GetTotalActions() uint64 {
+	if m != nil && m.TotalActions != nil {
+		return *m.TotalActions
+	}
+	return 0
+}
+
+func (m *BuildProgress) GetFinishedActions() uint64 {
+	if m != nil && m.FinishedActions != nil {
+		return *m.FinishedActions
+	}
+	return 0
+}
+
+func (m *BuildProgress) GetCurrentActions() uint64 {
+	if m != nil && m.CurrentActions != nil {
+		return *m.CurrentActions
+	}
+	return 0
+}
+
+func (m *BuildProgress) GetFailedActions() uint64 {
+	if m != nil && m.FailedActions != nil {
+		return *m.FailedActions
+	}
+	return 0
+}
+
+func init() {
+	proto.RegisterType((*BuildProgress)(nil), "soong_build_progress.BuildProgress")
+}
+
+func init() { proto.RegisterFile("build_progress.proto", fileDescriptor_a8a463f8e30dab2e) }
+
+var fileDescriptor_a8a463f8e30dab2e = []byte{
+	// 165 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x12, 0x49, 0x2a, 0xcd, 0xcc,
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+	0x75, 0x4c, 0x60, 0x75, 0xfc, 0x30, 0x71, 0x98, 0x52, 0x75, 0x2e, 0xfe, 0xe4, 0xd2, 0xa2, 0xa2,
+	0xd4, 0xbc, 0x12, 0xb8, 0x4a, 0x66, 0xb0, 0x4a, 0x3e, 0xa8, 0x30, 0x4c, 0xa1, 0x2a, 0x17, 0x5f,
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+	0xef, 0xfc, 0x00, 0x00, 0x00,
+}